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Guowang Forum • Composite film odor QQ group technology exchange record
Time: 2017-04-21 Source: Frontier of Packaging Reading: 9653
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Wenzhou Junchuan Machinery Equipment Co., Ltd.

广东包协情报委、《包装前沿》、北京华腾(广东国望)共同举办了“ 复合膜常见异味问题 在线技术交流会,包装前沿技术QQ总群、1群和三个微信群共约3000多位群友在线参加。 Aiming at the problem of complex film odors of flexible packaging companies, on the afternoon of April 20, the Guangdong Packaging Association Information Committee, "Packaging Frontier", and Beijing Huateng (Guangdong Guowang) jointly held an online technical exchange on " common film odor problems " At the conference, about 3,000 group friends from the total group of QQ, one group and three WeChat groups of cutting-edge packaging technology participated online.

谭固 ( 华腾福瑞的技术负责人 ) 主讲,为大家介绍了复合膜异味的危害、来源、控制和应对方法, 第二部分是自由探讨,就群友提出的异味相关的问题进行了在线交流和解答。 The exchange meeting was held in two parts. The first part was lectured by Beijing Huateng Tan Gu ( Technical Leader of Huateng Furui ) , and introduced the hazards, sources, control and coping methods of odor of composite film. The second part was free Discussions, online exchanges and answers to the problems related to odors raised by group friends.

复合膜常见的异味问题·主讲:北京华腾 ( 珠海福瑞 ) 谭固 I. Common Odor Problems of Composite Films · Speaker: Tan Gu of Beijing Huateng ( Zhuhai Furui )

Since the reform and opening up, with the improvement of people's living standards, the demand for composite flexible packaging has grown rapidly. The rapid development of composite flexible packaging has enriched the packaging form of goods, increased the display effect of goods, increased the added value of goods, and enriched people's material and cultural life. The colorful flexible packaging is beautiful and durable, making it the most important form of packaging for goods.

But at the same time, the odor problem of flexible packaging composite films has also plagued many plastic color printing enterprises, and even more troubled manufacturers of flexible packaging such as food and medicine.

、复合膜异味的危害 1. Harm of odor of composite film

The odor of flexible packaging materials not only adversely affects the sensory characteristics such as color, fragrance, and taste of the packaging contents, but also endangers the health of the end consumer to a certain extent, which is a problem that cannot be ignored in food safety.

When the situation is serious, it will cause resentment and discomfort to the packaging operator.

Off-flavors have the greatest impact on packaged foods. There is nothing more disappointing than the off-flavors of the food you eat. Therefore, food packaging has the most stringent requirements on off-flavors. Especially powdery, liquid foods and some light and fragrant foods, such as tea, milk powder, cheese, biscuits, cookies, corn flakes and other foods that are easy to taste and high in fat content (will absorb more fat-soluble transfer substances ), Also very sensitive to odor.

、复合膜异味的来源 2. Source of odor of composite film

There are two main sources of odors in flexible packaging composite films. One is that the composite film itself has an odor, and the other is that the composite film is affected by the external environment. Today we are mainly discussing the problem of odor generated by the composite film itself.

According to the composition of the composite film, we can divide the source of the odor generated by the composite film into five aspects: film , ink, solvent residue in ink, glue, solvent residue in glue.

1 )薄膜产生的异味 ( 1 ) Odor from the film

The odor generated by the film comes from the various additives of the film resin itself and its own low molecular weight substances.

Except for aluminum foil and paper, films used for flexible packaging are generally processed from high-molecular-weight resins. Resins are composed of molecules of different sizes. Different resins have different molecular weight distributions and low-molecular content. Low-molecular-weight substances are easily oxidized and volatilized during extrusion processing to produce off-flavors. In addition, residual monomers such as styrene, vinyl acetate, and acrylate in plastic resins can also produce off-odors.

At the same time, many additives need to be added to the resin to improve various properties. These additives are also the main source of film odor:

、开口剂 a , opening agent

Opening agents are mainly inorganic, usually calcium carbonate and silicon dioxide. The use of silicon dioxide as opening agents is easy to produce odor;

、爽滑剂 b , slip agent

Slip agents generally use oleic acid amides or diacid amide compounds, which generally have a sweet taste, but if you choose a slip agent that is not of high quality, it may also produce odor;

、抗静电剂 c 、 Antistatic agent

Its taste is very pungent, and it is generally not recommended to be used in films with high odor requirements;

、抗氧剂 d , antioxidant

It is usually a phenolic substance and has a certain taste, but in general, an antioxidant must be added to the film;

、色母料 e , color masterbatch

White masterbatch generally adds some waxes and stearates as dispersants and lubricants. These low-molecular substances will precipitate during processing and have a great taste. Therefore, they are generally used in the middle layer in multilayer co-extruded films.

At the same time, the film may also produce odor during processing:

、热分解产生的异味 a . Odor caused by thermal decomposition

EVA PP PE 类薄膜, EVA 由于热稳定性差,也容易产生异味,而 PP 聚乙烯类薄膜则异味比较小。 The films in direct contact with the packaging contents include EVA , PP, and PE films. EVA is also prone to odors due to its poor thermal stability, while PP polyethylene films have relatively low odors.

PE 聚乙烯热分解产生的异味。 At present, the more prominent is the odor generated by the thermal decomposition of PE polyethylene.

The odorous substances produced by the thermal decomposition of polyethylene can be roughly divided into two categories: aliphatic hydrocarbons and aromatic hydrocarbons. LDPE 热分解为 C3-C28 的饱和以及不饱和的碳氢化合物,其中短支链所产生的 C3-C6 化合物,对异味影响最大,由于挥发性较低,极性不高,这些物质在 PE 膜中能长时间存在。 According to research, LDPE is thermally decomposed into C3-C28 saturated and unsaturated hydrocarbons. Among them, C3-C6 compounds produced by short-chain branches have the greatest effect on odor. Due to their low volatility and low polarity, these substances Can exist in PE film for a long time.

、热氧化产生的异味 b . Odor caused by thermal oxidation

When plastic is processed under high temperature and high shear force, in addition to thermal decomposition, after extruding the film lip of the die, it can also undergo a thermal oxidation reaction with oxygen in the air, and the generated substances can also cause odors.

、电晕处理产生的异味 c . Odor caused by corona treatment

During the corona process of the film, carboxyl groups, hydroxyl groups, aldehydes, ketones and other groups and substances will be produced on the surface of the film. As the intensity of the corona treatment increases, the volatile small molecules (aldehydes and ketones) produced will also The more, and these small molecules are also one of the sources of odor.

Finally, odor may also be generated during storage: various plastic films will slowly age as storage time increases. If the storage time is too long, it will cause oxidation and decomposition under the action of oxygen, ozone, moisture, especially ultraviolet rays in the air, so that the film will produce odor. In addition, various additives in the film will slowly decompose, oxidize, precipitate and produce odors as the storage time increases.

2 )印刷和复合过程中溶剂残留产生的异味 ( 2 ) Odor from solvent residues during printing and lamination     

In the printing and dry lamination process, we inevitably need to use various solvents for dilution, and the odor of these solvents is relatively heavy. If it is in the production process, the solvent cannot be effectively evaporated, so that the solvent remains in the composite film. If the amount is too high, the composite film will naturally have the smell of residual solvents. Although everyone has used benzene-free and ketone-free inks, common solvents such as ethyl ester, n-propyl ester, and butyl ester still have relatively large odors, especially butyl ester. GB/T 10004-2008 中对复合包装袋的溶剂残留量做出了规定:溶剂残留总量≤ 5mg/ ㎡,其中苯类溶剂不得检出。 In GB / T 10004-2008 , the amount of solvent residues in composite packaging bags is specified: the total amount of solvent residues is ≤ 5mg / ㎡, and benzene solvents must not be detected.

In addition, excessive solvent residue will make the odor of the film more obvious, because the residual solvent will carry some odorous small molecule substances in the film during the process of penetrating the film to volatilize the small molecule substances in the film. The odor of the film becomes more obvious.

3 )油墨产生的异味 ( 3 ) Odor from ink

In addition to the residue of printing solvent, the ink may generate odor, and it may also generate odor. Gravure inks are composed of pigments, binders, auxiliaries, and solvents. Some binder resins, low-molecular-weight substances for auxiliaries, and pigment activators in some inks can produce odors.

4 )胶粘剂产生的异味 ( 4 ) Odor from adhesive

The low-molecular monomers and auxiliaries in the adhesive are all sources of odor.

、复合膜异味的控制 3. Control of odor of composite film

1 )原材料薄膜的选择 ( 1 ) Selection of raw material film     

6 个月内使用完比较合适。 Use films supplied by large manufacturers as much as possible (so that the quality and performance are relatively stable), and clearly put forward requirements for the odor of the films; if the color printing factory has its own blown film production line, then the choice of the film design formula must be considered first. Resins and various additives in the formulation should be as small as possible, and the processing temperature should be as low as possible. It is best to use the equipment with internal cooling or the production process of water blowing down; In addition, the film must follow the principle of first production, first use, and storage Avoid sunlight, and it is generally suitable to use it within 6 months.

2 )选择合适的油墨、降低印刷油墨溶剂残留 ( 2 ) Select appropriate ink and reduce solvent residue of printing ink

After the printing ink is transferred to the film, the solvent on the surface of the printing ink film first evaporates, and the solvent inside the printing ink film must diffuse and penetrate to the surface of the ink film before it can evaporate and dry in reverse. When drying is almost complete, the surface layer of the printed ink film has been cured, which limits the diffusion of the internal solvent, which causes the problem of residual solvents. The residual solvent contained in the printed matter is the main cause of the odor of plastic gravure flexible packaging. Its residual amount can be easily measured with a chromatograph to achieve qualitative or quantitative management.

Therefore, the control of printing solvent residues can be started from the following aspects:

、选择溶剂释放性好的油墨,并控制好混合溶剂中各组分的比例; a . Select the ink with good solvent release and control the proportion of each component in the mixed solvent;

We know that in order to meet the needs of printing or to consider the economy, mixed solvents are often added to the ink when printing. Each linker has its own true solvent, sub-solvent, and non-solvent.

The better the solubility, the greater the affinity between the binder resin and the solvent molecules, the better the solvent's solubility in the resin, the worse the resin's release properties to the solvent, and the worse the release properties, the more likely it is to cause residual solvents. problem. For a certain ink, the solvent release property is generally its inherent property, so when starting an ink, it is necessary to know the residual solvent tendency of the ink manufacturer in advance in order to make the corresponding treatment. The solvents contained in the printing ink layer are mixed solvents, and the volatilization speed of each solvent is different.

In this case, the volatilization of the solvent changes, and the volatile solvent escapes first, and the weakly volatile components remain, and the composition of the solvent changes, which cannot be obtained at a constant rate like a single solvent. With a single volatilization rate, the volatilization of the solvent gradually slows down. If the purity of the solvent is not satisfactory (such as containing too many high-boiling components) or excessive use of slow-drying solvents, serious residual solvent problems will normally occur.

、干燥条件; b , drying conditions;     

Drying conditions include drying temperature, air volume (wind speed), drying device structure, etc., which determine the drying efficiency. Poor drying will increase the amount of residual solvent, so create the best possible drying conditions. Increasing the wind temperature and air volume (wind speed) can undoubtedly strengthen the drying conditions, but it should be noted that if the printing ink layer is thick, if the drying is too fast, the surface of the ink layer will quickly condense and the internal solvent will not escape, but It will increase the residual solvent and produce odor.

、印刷速度; c , printing speed;     

The speed of the printing speed determines the length of the drying time. Therefore, it is necessary to ensure that the printing speed is gradually increased when the printing ink layer is sufficiently dry. However, if the speed is too fast, the drying of the film after printing cannot be fully guaranteed, especially the short distance between the last color printing and the rewinding unit (and most of the ink is large), which may easily cause the residual solvent to exceed the standard.

、车间环境; d , workshop environment;     

Humidity in the workshop environment has a significant effect on the amount of residue. The first is that moisture in the air enters the ink, causing the overall volatility of the solvent to deteriorate. The presence of large amounts of moisture in the workshop environment also inhibits the evaporation of solvents. Double the humidity and the ink will dry nearly twice as slowly. Therefore, under high humidity conditions, the printing speed should be slowed down and the contact between the ink and the air should be reduced to ensure that the ink is sufficiently dry. 70% ,当然也不能过于干燥,否则容易引起静电问题。 The humidity of the air in the printing workshop should generally not exceed 70% , and of course it should not be too dry, otherwise it will easily cause electrostatic problems.

、承印薄膜; e . Printing film;     

Films of different materials have different selective absorption tendencies for solvents. For example, films such as aluminum foil and polyester are non-absorbent films and generally have less residual solvents. Polypropylene films are prone to residual hydrocarbon solvents, while water-absorbing films (such as nylon and cellophane) are prone to residual alcohol solvents. There are also additives that are added to certain plastic films to affect the volatilization of solvents, thereby increasing the amount of residual solvents.

、其它; f , others;     

On the premise of meeting the basic requirements of printing, for multi-color printing, when designing the pattern, do not overlap too much. A special color can be used to prevent the local ink layer from being too thick; if conditions permit, the printing film can be entered into the curing room for curing, so that the ink is fully cured, and the residual solvent is fully volatilized before entering the next process.

3 )选择合适的胶粘剂、降低复合溶剂残留 ( 3 ) Select the appropriate adhesive and reduce the residual of composite solvent

、选择溶剂释放性好的胶粘剂 a.Select the adhesive with good solvent release

Experienced compound workers will have this experience. The solvent residues of different types of adhesives produced by the same material and the same process in the composite film are different. -OH , 与乙酸乙酯会形成氢键,这个氢键的形成,大大束缚了乙酯的挥发。 This is because the polyurethane adhesive molecule contains an active hydroxyl group ( -OH ) , which forms a hydrogen bond with ethyl acetate. The formation of this hydrogen bond greatly restricts the evaporation of ethyl ester. With different formulations of adhesives, the strength of the remaining ethyl esters forming hydrogen bonds is different. The stronger the hydrogen bonds, the more difficult the ethyl ester release, and the higher the solvent residue. UF2831 系列胶粘剂就是溶剂释放性特别好的产品。 Such as Beijing Huateng's UF2831 series adhesive is a product with particularly good solvent release.

、干燥条件 b , drying conditions

1250mm 宽的复合机,若复合机速要达到 120~150m/min ,排风量建议在 20000m ³ /h 以上。 The well-designed oven structure design is the basis for reducing the residual solvent. The oven temperature should be set according to the principle of step-by-step elevation. The temperature of the first stage of the oven should not be too high to prevent the film surface from drying quickly and inhibit the inner layer. The volatilization of the solvent; the wind speed of the air nozzle of the laminating machine of the compound machine should be high enough to ensure that the hot air blown out can reach the surface of the glue layer, so as to take away the solvent in the glue layer; the exhaust air volume of the oven is an important factor affecting the drying ability of the compound machine Generally, for a compound machine with a width of 1250mm , if the compound machine speed should reach 120 ~ 150m / min , the exhaust air volume is recommended to be above 20,000m³ / h .

、车间环境 c . Workshop environment

Similar to the control of printing ink solvent residues explained above.

、复合工艺 d 、 Composite process

The higher the coating amount, the thicker the glue layer, and the more solvent in the glue layer, the more difficult it is to dry. Therefore, if a high coating amount is required, the machine speed should be appropriately reduced; similarly, the faster the machine speed, The shorter the glue-coated film is in the oven, the more difficult it is to dry. Therefore, while increasing the compounding speed, the oven temperature should be appropriately increased, the exhaust air volume should be increased, and the return air should be turned off.

、涂胶薄膜的影响 e . The effect of coated film

The solvent absorption and release rates are different for different coated films. PET NY BOPP, 在通常的烘干条件下,温度距 BOPP 薄膜的熔点更近,其分子无规则活动更加剧烈,表现为对乙酸乙酯等有机溶剂的吸附速率加快,从而使其更难挥发。 The release order of ethyl acetate from commonly used films is PET NY BOPP. Under normal drying conditions, the temperature is closer to the melting point of BOPP film, and its irregular activities are more intense. The faster the adsorption rate of the solvent makes it more difficult to volatilize. BOPP 薄膜,要进一步降低其溶剂残留,难度更大些,必须同时考虑温度升高带来的溶剂释放速率和挥发速率的提高。 Therefore, it is more difficult for BOPP film to further reduce its solvent residue, and it is necessary to consider both the increase of the solvent release rate and the volatilization rate brought about by the temperature increase.

、溶剂中含水量 f , water content in solvent

The moisture in ethyl acetate will not only affect the composite strength and transparency, but also have a great effect on the volatilization of ethyl acetate. 0.05% )对减低溶剂残留是有帮助的。 Therefore, the use of qualified ethyl ester (water content ≤ 0.05% ) is helpful to reduce solvent residues.

、印刷油墨中的溶剂残留 g , solvent residues in printing inks

Residual solvents in printing inks are generally high-boiling solvents. During the compounding process, these high-boiling residual printing solvents will greatly reduce the volatilization rate of ethyl ester. Therefore, before compounding, you must confirm that the solvent residue of the printing film has reached the standard.

、复合膜异味来源的分析方法 4. Analytical method of odor source of composite film

There are various sources of odors produced by the composite film, so there are many types of odors, such as acid odor, sulfur odor, medicinal odor, tar odor, paraffin odor, petroleum odor, ink odor, soap odor, tar odor, and solvent odor. Wait. Moreover, odor is caused not only by one substance, but often by a mixture of several substances. At this time, it is even more difficult to describe the odor, because small changes in the composition of the mixture can cause differences in odor. Therefore, when the composite film has an odor, it is very important to analyze the source of the odor.

1 )首先确认是否有异味 ( 1 ) First confirm if there is any odor

Because odor is a sensory recognition, different people will have different conclusions, and the severity of the odor will not be the same. Then we need a unified way of understanding. GB/T 10004-2008 中规定了异味的检测方法:打开包装箱及内衬的包装膜,立刻闻是否有异味;取 10cm*10cm 的薄膜一张,裁成条状,放入锥形瓶中,再加入 150ml 的蒸馏水,盖上盖子密封,放入 60 ℃的烘箱或水浴中, 30min 后取出,打开盖子,闻水蒸气的气味,判断是否有异味。 GB / T 10004-2008 specifies the odor detection method: open the packaging box and the inner packaging film and immediately smell the odor; take a piece of 10cm * 10cm film, cut it into strips, and put it in a conical bottle Then, add 150ml of distilled water, seal with a lid, put it in an oven or water bath at 60 ℃, take it out after 30min , open the lid, smell the smell of water vapor, and judge whether there is a strange smell.

After confirming the odor, it is necessary to confirm which part (and possibly several parts) of the composite film originated from the odor, including film, ink, glue, printing solvent residue, and composite solvent residue.

2 )薄膜是最好排除的部分 ( 2 ) the film is the best excluded part

10cm*10cm ,若气味不明显,则可以成倍增加取样量),剪成条状装入无气味的玻璃瓶中密封,放入 60 ℃的烘箱或水浴中, 1 小时后开瓶闻气味,与复合膜气味相同或相近的薄膜就是异味的来源,反之则不是异味的来源。 If the composite film has a strange smell, then take one of the composite film and the light film of the same batch ( 10cm * 10cm , if the smell is not obvious, you can double the sampling volume), cut into strips and load The odorless glass bottle is sealed and placed in an oven or water bath at 60 ℃. After 1 hour, the bottle is opened to smell the odor. The film with the same or similar odor to the composite film is the source of the odor, otherwise it is not the odor source. It should be noted here that if the storage time of the plastic film in the oven is too long, it may have a burnt smell.

3 )印刷溶剂残留和复合溶剂残留 ( 3 ) Residues of printing solvents and composite solvents

Solvent residues need to be detected with the aid of a gas chromatograph. If a serious excess of solvent residues is found, it is most likely that the odor produced by the residual solvents (which needs to be compared with the odor of the relevant solvent). Residual may cause odor.

4 )胶粘剂异味 ( 4 ) Adhesive odor

Can be judged by direct detection and indirect detection. PET/PET, 因为 PET 不易产生异味),再做气味对比分析。 The direct detection is to take the adhesive sample and test the composition of volatile substances by meteorological chromatography. However, because there is more than one odor-generating substance and the content may be very low, it may not be detected. The glue used and the odor-free glue are compounded with the same structure at the same time ( PET / PET is recommended , because PET does not easily produce odor), and then the odor comparison analysis is performed.

5 )油墨异味 ( 5 ) Ink odor

For the analysis method of ink odor, you can refer to the odor analysis of the adhesive, but when you do the detection and comparison test, you only need to use the uncompounded printed film and the odorous composite film for the odor matching experiment.

、复合膜异味案例分析 5 、 Analysis of odor of composite film

PET/CPP 的订单被投诉有异味被退货,虽然单个袋子气味并不比严重,但整箱开箱时,大家都觉得气味比较刺鼻,也比较浓。 A customer 's order for a PET / CPP was complained of odor and returned. Although the odor of a single bag was not serious, everyone felt that the odor was harsh and strong when the box was opened.

3.05mg/ ㎡,其中乙酯残留量在 2.1mg/ ㎡,未发现苯类和酮类溶剂残留。 First, we used a weather chromatograph to perform solvent residue detection on the returned bags. We found that the total solvent residue was 3.05 mg / ㎡, of which the ethyl ester residue was 2.1 mg / ㎡, and no benzene and ketone solvents were found. Therefore, odors caused by solvent residues are eliminated.

Since the customer still has unfinished production for this order, we quickly found the same batch of raw materials used in the production of the problem product, and immediately performed a odor comparison test. First, we put different combinations of materials into five sealed glass bottles with no odor and numbered them, as shown below:

PET 光膜;② PET 印刷膜;③ CPP 膜;④ PET 印刷膜 +CPP 膜(未涂胶复合);⑤问题样品袋( PET 印刷 /CPP 复合膜)。 PET light film; ② PET printing film; ③ CPP film; ④ PET printing film + CPP film (uncoated composite); ⑤ Problem sample bag ( PET printing / CPP composite film).

60 ℃的恒温烘箱中烘烤, 1 小时后同时取出,并开盖闻气味,结果如下: Then, five bottles were simultaneously baked in a constant-temperature oven at 60 ° C , and taken out at the same time after 1 hour, and the lid was opened to smell the smell. The results are as follows:

① and ③ bottles only have a slight odor, and do not match the odor of ⑤ (exclude film odor);

There is a pungent odor in the bottles ② and ④, and it is very close to the odor in the bottle ⑤ (excluding the odor of glue, and it can be determined that the ink has an odor).

The result is very obvious, that is, the odor produced by the odor of the ink. Through communication and understanding of the situation, the customer just changed the ink supplier in the early period, and after adjustment by the ink manufacturer, the problem of odor was also quickly resolved.

Second, specific cases related to free communication and odor

、干式复合 PET/AL/PE 面膜袋,袋内有明显气味,请问怎么解决? 1. Dry composite PET / AL / PE mask bag, there is obvious odor in the bag, how to solve it?

Guangdong Baowang Xiao Baoping:

The first thing to do is determine what caused the odor. The first thing to do is to remove solvent residues and determine what odor is.

Beijing Huateng Fan Zhiguo:

First of all, it is necessary to determine what is the reason, whether it is the composite process, the printing, the curing, the ink and glue problems, and then the right medicine. There are many reasons for this problem, both subjective and objective.

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

60 ℃烘箱 10min ,开袋闻气味,如果气味一致,那么胶水的嫌疑最大;如果反过来,做的袋子没有异味,则 PE 膜的嫌疑最大。 For this question, we can make some preliminary judgments. First, make a bag with the heat-sealing layer of the packaging bag facing outward and the printed layer facing inward. Inflate with the normal bag at the same time, put it in an oven at 60 ℃ for 10 minutes , and open the bag to smell If the smell is the same, then the suspicion of glue is the biggest; if the bag is made without odor, the suspicion of PE film is the biggest.

AL 层的结构,我们可以认为 AL 层是不可被异味穿透的。 Like this structure containing the AL layer, we can think that the AL layer is not penetrated by odors.

AL 层作为分割面, AL 层的表面是 PET 、胶水、油墨、复合溶剂残留、印刷溶剂残留; AL 层的下面是 PE 、胶水、复合溶剂残留。 The AL layer is used as a dividing surface, and the surface of the AL layer is PET , glue, ink, composite solvent residue, and printing solvent residue; under the AL layer, PE , glue, and composite solvent residue.

If the smell of the two bags is inconsistent, the same items on both sides can be ruled out.

If the two bags smell the same, you can focus on the same items.

Of course, this is a simple method and not particularly rigorous. If you need to determine the cause, you still need to follow the previous analysis steps.

、茶叶包装 PET/VMPET/PE, 茶叶开封后有股塑料的焦臭味。 2 , tea packaging PET / VMPET / PE, tea leaves have a burnt smell of plastic.

Guangdong Baowang Xiao Baoping:

In this case, it should be considered that the additive of the material is more likely to precipitate.

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

PE 不会太厚,如果 PE 中加了很多回收料,加之膜又薄,就很容易产生异味。 Tea packaging is lightweight packaging. Generally, the PE used is not too thick. If PE is added with a lot of recycled materials and the film is thin, it will easily produce odor. The rigorous solution to the problem still needs to be eliminated one by one according to the steps mentioned above. We are now discussing some important points to focus on.

VMPET! Another point in this case that cannot be ignored is VMPET!

PET 不容易有异味,但是经过真空镀铝后, PET 有可能在高温状态下氧化或热降解产生一些低分子物质或醛类物质。 Although PET is not susceptible to odor, after vacuum aluminum plating, PET may oxidize or thermally degrade under high temperature to produce some low molecular substances or aldehydes.

Guangdong Baowang Xiao Baoping:

Yes, in this case, it will be released when heat-sealed at high temperature, which will cause odor.

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

Xiao Gong is right that many small molecules will be released when heat-sealed at high temperature. VMPET 的味道,我们取了客户的 VMPET 放入玻璃瓶中烘烤,与茶叶袋开袋后的气味一致。 Later, after analysis, it was the taste of VMPET . We took the customer's VMPET and baked it in a glass bottle, which was consistent with the smell after the tea bag was opened.

Liu Jiwu of plastic packaging:

This is the odor caused by the film.

"Packaging Frontier" Shen:

PET/VMPET/PE 这种结构, PE 和镀铝 PET 都是极易产生异味的源头? Can it be said that, for any structure like PET / VMPET / PE , PE and aluminized PET are the sources of odor easily?

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

Yes, this is the key point that requires focused control.

"Packaging Frontier" Shen:

PE 供应商沟通,调整 PE 配方呢? So, when the company is producing tea packaging, does it need to communicate with his PE supplier to adjust the PE formula?

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

PE 是使用在食品包装上。 The main thing is to communicate with the supplier first, emphasizing that PE is used in food packaging. Not just tea, but also other food packaging. All contents with strict odor requirements are required, such as food, medicine, cosmetics, etc.

Shandong Jincheng Dingtai Packaging Zhuang Jinhong:

CPP 代替 PE 来做, CPP 的阻隔性或无异味性要优于 PE With this structure, we use CPP instead of PE in actual production , and CPP has better barrier properties or no odor than PE .

Guangdong Baowang Xiao Baoping:

CPP PE 的柔软性要差。 Tea bags must be evacuated. CPP is less flexible than PE .

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

In fact, as long as it is suitable for the contents of the package, like some daily necessities packaging, the odor requirements are lower.

Beijing Huateng Fan Zhiguo:

In fact, there are many small manufacturers. In order to reduce costs, the proportion of filler added is out of balance.

"Packaging Frontier" Shen:

It seems that a major factor in solving odor is to choose a film that meets the requirements of food packaging.

 

、大米袋无溶剂复合 NY/PE ,有异味问题,如何处理? 3 , rice bag solvent-free composite NY / PE , there is a problem of odor, how to deal with it? what is the reason?

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

NY/PE 机速可以开到很高, PE 又厚,所以重点关注胶水、溶残和 PE 造成的异味。 Rice bags are generally heavy-duty, with a high coating volume and high NY / PE machine speed, and a thick PE , so focus on the odor caused by glue, residue, and PE .

Chongqing Jutlu Minghua:

Personally, I think that for the problem of odor, we must first understand the source of the odor, and then solve it in a targeted manner. 膜是否有异味? Is there a odor in NY film? Does the printed film smell strange? 膜是否有异味? Does the PE film have an odor?

Beijing Huateng Fan Zhiguo:

Solvent-free compounding means that there is no solvent in the compounding step, and the residue of the compounding step can be excluded. Mainly consider the printing process and materials.

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

PE 一般使用添加了茂金属的 PE, 这也是异味的来源之一。 In order to improve the drop resistance of rice bags, PE generally uses metallocene-added PE, which is also one of the sources of odor.

Beijing Huateng Fan Zhiguo:

On the other hand, solvent-free glue may also generate odors, so everyone needs to pay attention.

High barrier film Zheng:

Solvent-free compounding has no drying tunnel heating, so the possibility of odor generation is smaller than solvent-based dry compounding.

Chongqing Jutlu Minghua:

However, solvent-free compounding also brings about relatively large odor problems, which can be felt in the workshop. Especially solvent-free for some brands. Many people can determine whether it is solvent-free compounding or dry compounding by smelling. Therefore, determine the source according to the type of odor. There is no doubt that the solvent-free glue has a large odor, especially some domestic solvent-free glues are more serious.

Beijing Huateng Fan Zhiguo:

I once encountered a color printing factory that used other solvent-free composites to have a taste. With Huateng's solvent-free, there was no such taste.

Upgrade the dry compound machine to a solvent-free compound machine:

Solvent-free glue will have a strong odor mainly due to the problem of raw materials. Cheap solvent-free glue will use castor oil to replace some of the ingredients, resulting in lower cost and price, so it is normal to have offensive odor.

 

、我们现在做食品包装, 4 层复合,已经做成成品袋子了,异味明显,有什么好的处理办法吗? 4. We are now doing food packaging. The 4- layer compound has been made into a finished bag. The smell is obvious. Is there any good way to deal with it? We use ester-soluble inks.

"Packaging Frontier" Shen:

Generally speaking, there is no way to improve the bag, right? Is it possible that ester-soluble inks can cause odors?

-- 姜吉野: Dalian Yihai Packaging - Jiang Yoshino:

Only for a while in the maturation room.

Beijing Huateng Fan Zhiguo:

In this case, it is a stupid way to mature it, or put it in a ventilated place for a period of time.

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

First detect the solvent residue. If it is the odor caused by the solvent residue, it can still be post-processed to eliminate the odor. If it is caused by other reasons, it is more difficult to eliminate the odor.

 

、制袋后的复合薄膜有异味,客户投诉是聚乙烯薄膜的异味。 5. After the bag is made, the composite film has an odor, and the customer complained that it was an odor of the polyethylene film. Do I need to change the film? Or something else?

Guangdong Baowang Xiao Baoping:

If the problem is really the odor caused by the film, it must be replaced

( 珠海福瑞 ) 谭固: Beijing Huateng ( Zhuhai Furui ) Tan Gu:

The composite film can be made into a bag, but without heat sealing and sealing with tape. Compare the odor with the normal bag. If the bag without heat sealing has no odor, the odor is generated during heat sealing.

Third, the conclusion

There are many reasons for the odor of the composite film. By in-depth understanding of the source of the odor and the corresponding elimination methods, no matter what kind of odor problem the company encounters, it can find the source one by one to solve the problem.

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