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Guowang Forum • Polyurethane Ink Curing Causes and Solutions
Time: 2017-06-01 Source: Cutting Edge of Packaging Read: 10810 times
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31 日下午,由广东省包协情报委•《包装前沿》联合主办的“ 聚氨酯油墨固化不良的原因及解决技术探析”在线交流活动在包装前沿技术交流 QQ 群、微信群同步举办,约 4000 余位群友在线参加。 On the afternoon of May 31 , the online communication event of " Polyurethane Ink Poor Curing and Solution Technology Analysis" co-sponsored by the Guangdong Provincial Packaging Association Information Committee and "Packaging Frontier" was held simultaneously in the QQ frontier group and WeChat group of packaging frontier technology exchange More than 4,000 group friends participated online. PET/MPET PET/AL BOPP/MPET BOPP/AL 等表层结构时,经常会出现袋子折叠一段时间后起皱或热封处容易离层等固化不良现象,进行了深入的分析,并提供了相应的解决方案。 The event invited Mr. Lu Minghua of Beijing Huateng (Head of Huateng Chongqing Jute) to give a lecture. When the general manager Lu targets the surface structure of composite PET / MPET , PET / AL , BOPP / MPET , BOPP / AL , the bag will often fold for a period of time. Post-wrinkling or heat sealing is prone to delamination and other poor curing phenomena. An in-depth analysis is performed and corresponding solutions are provided. At the same time, Huateng technical service team communicated with group friends online.

@ 的原因及解决技术探析•主讲:吕铭华 I. Analysis of the Causes of Poor Curing of Polyurethane Ink @ and the Solution Technology • Speaker: Lu Minghua

Adhesive incomplete curing is one of the most common quality problems in the lamination process.

There are many reasons for this problem, such as inaccurate mixing ratio, excessive moisture or alcohol content in the solvent, too much environmental humidity, improper storage of the remaining glue, insufficient crosslinking of the adhesive itself, etc. will cause incomplete curing results. Among them, it is particularly important to pay attention to the effect of polyurethane ink on the non-curing of the adhesive.

Because polyurethane inks and adhesives do not match, the following phenomena may occur:

Some flexible packaging customers report that when the roll film produced by them is automatically packaged at their customers, there is a phenomenon of wrinkling at the edge, or broken bags during hot filling.

1~2h ),封边处出现皱褶起层现象。 The produced bag is left for a period of time (about 1 ~ 2h ) after the bag is made , and the phenomenon of wrinkle layer appears at the edge of the seal.

Some bags were folded when they were boxed. After a period of time, delamination occurred at the crease.

: Here is a specific case :


PET12/VMPET12/CPP60 The structure of this sample is: PET12 / VMPET12 / CPP60

The sample situation analysis is as follows:

PET/VMPET 剥离强度 1.5N/15mm ,剥离时油墨与镀铝之间分开,因剥离角度不同会有较少油墨或镀铝转移,胶水有发粘不干现象, 80 ℃烘箱继续熟化 24h ,发粘现象无明显变化,将剥离样条暴露在潮湿空气中 24h ,样条仍然发粘。 1. The peel strength of outer PET / VMPET is 1.5N / 15mm . When peeling, the ink is separated from the aluminization. There will be less ink or aluminization transfer due to different peeling angles. The glue will be sticky and dry. After curing for 24 hours , the tackiness did not change significantly. When the stripped splines were exposed to moist air for 24 hours , the splines remained tacky.

VMPET/CPP 剥离强度 3.5N/15mm ,没有发粘不干现象。 2. One-shot composite inner VMPET / CPP peeling strength is 3.5N / 15mm , without stickiness.

-OH 成分,说明胶粘剂中的固化剂已有一部分被消耗。 Conclusion: The non-drying component is -OH , which means that the curing agent in the adhesive has been partially consumed.

This is the phenomenon of several customers' products.

Cause Analysis:

1. It is a one-time molding during processing and molding, and there is no additional compounding during the production process.

=2:3:5 ,残留总量 3.6mg/m 2 , 其中醇类溶剂 0.2mg/m 2 2. The ink is benzene-free and ketone-free polyurethane ink, and the solvent is ethanol: ethyl acetate: n-propyl acetate = 2: 3: 5 , and the total residual amount is 3.6 mg / m 2 , of which the alcohol solvent is 0.2 mg / m 2 .

Could this be that the curing agent in the adhesive was consumed by the polyurethane ink binder?

, 这种提法是不科学的,或者说是根本没有单组分聚氨酯复合用油墨(用在其他用途上除外)。 The one-component polyurethane composite inks that everyone mentions now are unscientific, or there is no one-component polyurethane composite ink (except for other uses).

, 因为聚氨酯油墨加入固化剂后,其寿命只有四到六小时。 This is mainly a product launched by the ink factory to meet the requirements of the printing plant for the life of the ink , because the polyurethane ink has a life of only four to six hours after adding the curing agent. , 没有单组分之说。 When there was a polyurethane composite ink, there were only two-component inks , and there was no single -component ink . , 对普通型聚氨酯粘合剂带来很大的稳患。 In this way, when used, it brings great stability to the ordinary polyurethane adhesive.

-NH 2 -OH 两类,尤其以 -NH 2 为主。 Polyurethane linker has active hydrogen functional groups on the molecular terminal, generally -NH 2 and -OH , especially -NH 2 is the main type. Thus, there is a problem that the amine value fluctuates as the molecular weight of the binder fluctuates. 2% 左右。 The data of the binder is generally about 2% of the amine value . -NH 2 If such a binder ink is used, and no ink curing agent is used in printing, a large amount of -NH 2 remains in the ink layer .

3%~4% 左右的固化剂(硬化剂),但是一般只限于大底色,或者水煮、蒸煮产品。 In general, about 3% to 4% of the curing agent (hardener) is added to the ink , but it is generally limited to large background colors, or boiled and cooked products. Because the ink curing agent is an aliphatic curing agent, the unit price is relatively high. Considering the cost and the shelf life of the ink, general products usually do not add a curing agent.

When compounding, when the ink curing agent contacts the glue curing agent, the following reactions will occur quickly:

R-NH-CO-NH-RN=C=O -R-NH 2 + O = C = NRN = C = O R-NH-CO-NH-RN = C = O

-NH 2 -N=C=O 反应活性远高于 -OH This reaction rate is theoretically an instantaneous fast reaction, because -NH 2 and -N = C = O are far more reactive than -OH . ( 其官能团是 -OH) 反应,已有部分被油墨固化剂消耗掉,导致复合膜的粘接固化效果不完全。 Therefore, the adhesive curing agent has not yet reacted with the adhesive main agent ( its functional group is -OH) , and has been partially consumed by the ink curing agent, resulting in incomplete bonding and curing effect of the composite film.

How to deal with such problems?

Because the problem points are very clear, in fact, it is not complicated to solve them. Everyone can notice such problems, be vigilant, and generally there will be no problems.

The specific solution is as follows:

1. Select a supplier with stable product quality

2. The use of ink and glue must be relatively stable

—3 , Matching test when changing ink or glue

10%~20% 固化剂。 4. Add ink curing agent during printing. According to the actual curing situation, add 10% ~ 20% more curing agent when mixing .

UK3160DK/UK5060 Of course, in order to better help customers solve such problems, Beijing Huateng is also constantly working on the improvement of adhesives, relying on strong technology to develop a fast curing adhesive UK3160DK / UK5060 . There are also very good results in solving such problems.

Free communication

:PET/AL PET/MPET ,复合完了没事,过一会就鼓起白泡来了,出现好几次了。 1. Jiahe Wansheng Alvin : PET / AL , PET / MPET , it's okay to finish the compounding. After a while, white bubbles will come up and appear several times. 3.5gsm, 找不到准确原因。 Printing solvent residues have been eliminated, and the sizing amount is enough, 3.5gsm, no exact reason can be found. What is going on?

( 珠海福瑞 ) : 整卷还是卷表? Beijing Huateng ( Zhuhai Furui ) Tan : The whole volume or the watch?

: 首先确定“白泡”是真空状还是含有气体。 Chongqing Jutelu Minghua : First determine whether the "white bubble" is vacuum or contains gas. Secondly, see if there is a regular position, whether the core is the same outside.

If it is a gas-containing bubble and it is not present when the aircraft is off, then there are usually only two cases: one is the collection of residual solvents,

The second is that the curing agent in the adhesive reacts with moisture to generate carbon dioxide to form bubbles.

: Jiahe Wansheng Alvin :

, 是后期鼓起来的,只有油墨部分有 , 加大上胶量到 5gsm 左右,用放大镜看有火山状。 The size of the bubble sesame was swollen in the later stage, only the ink part was there . Increase the sizing amount to about 5gsm . Use a magnifying glass to see a volcano.

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

Does the ink part have a white backing?

: Jiahe Wansheng Alvin :

White ink bubbles are more pronounced.

: Chongqing Jutlu Minghua :

After compounding, is it matured or is it recombined directly?

- 高桢 : Beijing Huateng Wanfuda - Gao Ye :

? Is the printed film residue exceeding the standard ?

: Guangdong Guowang Zheng Fangming :

, 可以在复合前检测一下印刷膜的溶剂残留量 , 看看都有哪些溶剂残余。 If there is only the ink position , you can check the solvent residue of the printed film before laminating to see what solvent residues are.

- 高桢: Beijing Huateng Wanfuda - Gao Ye:

AL 都是阻隔性好的材料,如果有溶剂残留复合时没有挥发掉,在固化时释放不出来,就会凝聚产生气泡。 PET film and AL are both materials with good barrier properties. If there is a solvent residue and the compound is not volatilized, and it is not released during curing, bubbles will be formed.

Jiahe Wansheng Alvin:

2 次烘干,放置了一会就起气泡了。 I printed the film. I dried it twice, and after a while, it blistered.

: Chongqing Jutlu Minghua :

After the first composite layer, the second layer is directly applied or after the aging is repeated?

: Jiahe Wansheng Alvin :

2 遍的时候,一过烘箱泡就起来了。 When repeating the second pass, the oven soaked up.

: Chongqing Jutlu Minghua :

Have you tried aging for a while before recombining it twice? Does "bubble after leaving for a while" mean a single film or an outside film or a whole film?

: Jiahe Wansheng Alvin :

, 用放大镜看,就像火山口一样 , 里面有胶,感觉就像有水的感觉。 As soon as it was heated, bubbles formed. The whole volume , viewed with a magnifying glass, was like a crater . There was glue in it and it felt like water.

: Chongqing Jutlu Minghua :

personal suggestion:

1. The film winding tension and taper must be matched, and the film should be tightened as much as possible.

12 小时后再复合第二遍。 2. After compounding at low temperature for 12 hours, compound again.

3. Measure the coating amount to ensure the dry glue amount.

: Beijing Huateng Fan Zhiguo :

? Can you provide the temperature set by the compound machine during operation ?

: Jiahe Wansheng Alvin :

This is especially noticeable when the rubber roller is not used.

45 55 65 75 Laminating machine temperature setting: 45 55 65 75

Beijing Huateng Fan Zhiguo:

With such a temperature setting, the bubbles appearing will not be shaped like a crater with a magnifying glass.

: Jiahe Wansheng Alvin :

With a homogenizing roller, it is much better.

: Mitsui Chemicals Li Weigang :

Check the oven temperature and don't start too high.

: Chongqing Jutlu Minghua :

Is the surface tension detected at the ink position?

If there is no problem with the surface tension at the ink position, you can try it by referring to the method I just mentioned, and we can communicate the test results later. If necessary, you can send samples to us and we assist in analysis.

: Jiahe Wansheng Alvin :

When compounded, the tension is great.

: Beijing Huateng Fan Zhiguo :

? 最好检测印刷和复合的溶剂残留。 There is also a question, does the order of temperature setting match the order of the machine ? It is best to detect the solvent residue of printing and compounding. Polyester and polyester aluminizing are high-barrier materials, and the permeability is relatively poor. It is recommended to check the printing and compounding processes, including the purity of the solvent.

: Jiahe Wansheng Alvin :

OK, I do n’t have a gas chromatograph now.

Beijing Huateng Fan Zhiguo:

Low solvent purity will affect the volatilization of the solvent and may cause high solvent residues.

: Jiahe Wansheng Alvin :

No test, it tastes sensory.

: Beijing Huateng Fan Zhiguo :

Then test it first and then analyze it step by step.

: Jiahe Wansheng Alvin :

I took a sample and asked my friends to analyze what was in it, analyzed the results, and communicated with the experts.

: Chongqing Jutlu Minghua :

Okay, keep updated on new developments.

: Beijing Huateng Fan Zhiguo :

This is sometimes related to climate and temperature.

:PET1.2// 铝箔 0.65u//PE4.2c ,铝箔和 PE 复合不牢,撕出来后 PE 膜上面还带有粘性。 2. Huasheng Film Industry : PET1.2 // aluminum foil 0.65u // PE4.2c , the aluminum foil and PE are not firmly compounded, and the PE film is still sticky after being torn out . PE 膜去复合却能牢固,虽然不是特别牢。 However, customers can use other specifications of PE film to compound, but it can be strong, although not particularly strong. May I ask what is the reason? PE film corona is fine.

PET/ 铝箔 /PE4.2c ,却又是很牢固的。 But the customer sent the film, and I took it to a nearby printing factory for lamination, which was also PET / aluminum foil / PE4.2c , but it was very strong. 5 1 7 ,熟化时间 48h The glue ratio is 5 : 1 : 7 and the aging time is 48h .

- 高桢 : Beijing Huateng Wanfuda - Gao Ye :

One possibility is that the climate is different, the glue is sticky, the weather is humid, and some of the curing agent is eaten. There are water or alcohol solvents in the solvent.

: Chongqing Jutlu Minghua :

PE ,状况也是有可能有一些差异的,因为 PE 膜里的油酸酰胺以及芥酸酰胺也会消耗部分固化剂,但是根据上述描述来说,应该是胶水配比中固化剂的量相对偏少造成的。 This situation needs to be verified through orthogonal experiments to find out the problem. The same glue ratio, the same process, and different PE compounds may have different conditions, because the oleic acid amide and erucamide in the PE film. Part of the curing agent will also be consumed, but according to the above description, it should be caused by the relatively small amount of curing agent in the glue ratio.

PE 膜上面还带有粘性。但是客户用别的规格的 PE 膜去复合却会牢。虽然不是特别牢”,说明也不是一个正常状态,只是情况严重与轻微的差别。 "The PE film is still sticky after being torn out . However, the customer will use other types of PE film to compound it, but it will be strong . Although it is not particularly strong," it is not a normal state, but the situation is serious and slightly different.

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

al/PE 剥开还有粘性吗? Is it still sticky to peel off al / PE after the composite film has been cured at other customers ?

- 华生膜业: Guangdong - Huasheng Film Industry:

I took the film to another factory for lamination, and the result was that the lamination strength was very good and I couldn't tear it off.

: Chongqing Jutlu Minghua :

PE 膜看看效果如何? You can increase the amount of curing agent and compound the two kinds of PE film to see the effect. PE 膜,再看看效果,应该就会有答案了。 At the same time, two kinds of PE film are compounded with the adhesive of the compound plant near you , and if you look at the effect, you should have the answer.

- 华生膜业 : Guangdong - Huasheng Film Industry :

I asked the customer to send me the film that said it was always insecure. After I received it, I took it to a nearby manufacturer to help me try it out. The result in the morning is that the composite strength is very good, and I ca n’t tear it apart. Torn.

- 高桢: Beijing Huateng Wanfuda - Gao Ye:

Then pass.

- 华生膜业 : Guangdong - Huasheng Film Industry :

The manufacturer told me that it may be the cause of insufficient glue, but the customer directly denied it. It's okay to say how to compound other films, and the specifications for compounding are not strong.

: Chongqing Jutlu Minghua :

It is recommended to conduct a field test to find the cause.

- 华生膜业: Guangdong - Huasheng Film Industry:

Yes, I think so too.

3 , Mr. Hui Teli Chen, Jiangyin Outlet Color Printing Yang Bin, Dalian Yihai Packaging Jiang Yoshio: What should I do if the bottom of the roll is wrinkled when composite aluminum-containing structure is used? , 卷底起皱怎么办? In particular, the printing layer and aluminum foil layer (dry coating) and heat sealing layer are solvent-free .

: Chongqing Jutlu Minghua :

This refers to the problem of core wrinkles, right? It is not a problem of poor curing.

: Thursday on Hefei Meibang :

6 英寸纸管会好些。 A 6 -inch paper tube would be better. The main problem is the taper of the winding tension, which causes the inner loose and the outer tight, and wrinkles.

: Chongqing Jutlu Minghua :

Core wrinkle is a common problem in the composite packaging industry and should be related to many factors.

Pay attention to the following factors:

6 英寸纸管比 3 英寸要好,尤其是加硬的。 1 , 6 inch paper tubes are better than 3 inches, especially hardened.

2. Matching of material structure with winding tension and taper.

3 , ripening conditions.

4. The flatness of the core joint is also important.

( 珠海福瑞 ) 谭: Beijing Huateng ( Zhuhai Furui ) Tan:

There should be no joints as close to the core as possible.

: Chongqing Jutlu Minghua :

The higher the curing temperature, the greater the thermal expansion of the film, the greater the tightening stress on the film, and the more easily wrinkles are generated.

, 对于褶皱问题,熟化温度低一点效果要更好。 The curing temperature and time need to refer to the curing requirements of the adhesive . For wrinkles, a lower curing temperature is more effective.

It is particularly emphasized that the treatment of the joint must be careful. If you observe carefully, you will find that there are the most folds before and after the joint.

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

2~4 小时左右重新复卷 . If the wrinkles can be clearly seen from the end surface, it should be rerolled about 2 to 4 hours after lamination .

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

What I want to ask is the solution to live wrinkles.

: Chongqing Jutlu Minghua :

Eliminate wrinkles:

6 英寸纸管比 3 英寸要好,尽量使用加硬的纸管,有的客户使用铝箔膜里的铁管芯 1 , 6 -inch paper tube is better than 3 inches, try to use hardened paper tube, some customers use iron core in aluminum foil film

2. Matching of material structure with winding tension and taper.

3 , ripening conditions, the ripening temperature is appropriately reduced.

4. The joint must be flat.

If the wrinkle is to be recovered, it is generally placed on the compound roll of the laminating machine for hot rolling and rewinding.

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

Are aluminum-plated materials more prone to wrinkles?

: Chongqing Jutlu Minghua :

AL 等刚性材料褶皱的情况会更多一些。 The folds of rigid materials such as PET and AL will be more.

Third, the conclusion

Because the problem of the ink causes poor curing of the glue, it has attracted the attention of many enterprises, and the occurrence of such problems is becoming less and less. In production, the company shall maintain proper stability of the raw materials and processes of the products, and shall follow the small, medium and large test principles when changing to avoid loss of batch quality. ! 这点应引起大家的注意。 At the same time, suppliers should pay attention to product quality. Polyurethane inks cause non-curing. It seems that the ink is caused by the ink binder. Many ink factories do not make ink binders themselves, so the quality of ink binder suppliers is stable. It's also important ! This should be brought to your attention.

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