KR101902955B1 - Highly stretchable moisture-curable reactive polyurethane hot-melt adhesive, and production method thereof - Google Patents

Abstract

Provided is a polyurethane hot melt adhesive composition which has a short curing time while initial adhesion duration can be adjusted, and secures excellent adhesive strength and stretchability. To this end, the polyurethane hot melt adhesive composition contains a compound in which polyester polyol having molecular weight of 4000-6000 is modified with caprolactam, polyester polyol having molecular weight of 2000-3000, isocyanate, and a chain extender. Moreover, provided is a production method thereof.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a highly adhesive and highly elastic moisture-curing reactive polyurethane hot-melt adhesive composition and a production method thereof,

The present invention relates to a moisture-curing reactive polyurethane hot-melt adhesive composition, and more particularly, to a polyurethane hot-melt adhesive composition having excellent adhesion strength and stretchability, capable of adjusting initial bonding time, And a manufacturing method thereof.

Polyurethane compositions used as hot melt adhesives are made by reacting isocyanates with high molecular weight polyols such as polyester polyols or polyether polyols called polyols. Since such a polyurethane hot-melt adhesive composition is applied to an adherend in a molten state and adhered to the adherend, it is easy to adhere, is very resistant to moisture, has high resistance to various chemicals, It has been used in industry.

Korean Patent Publication No. 2004-7015268 discloses polyurethanes for hot melt adhesives obtained by reacting polyesters, polyisocyanates and chain extenders formed from dimer fatty acid and / or dimer fatty acid diols. However, since the conventional polyurethane hot melt adhesive composition uses diphenylmethane diisocyanate as a raw material, it is yellowed when exposed to ultraviolet rays, and has a commercial limitation. When the aliphatic isocyanate is used to solve this problem, there is a problem that the adhesive strength is lowered due to the low reactivity of the aliphatic isocyanate.

In addition, the polyurethane hot-melt adhesive composition needs to appropriately adjust the processing temperature in consideration of the melt viscosity, the curing temperature, and the like, and if the processing temperature is too high during the processing, the curing reaction is caused in advance.

Published Japanese Patent Application No. 2004-7015268 (published Nov. 10, 2004)

In the present invention, a polyester polyol having a molecular weight of 4000 to 6000 is modified with caprolactam, a polyester polyol having a molecular weight of 2,000 to 3,000, an isocyanate and a chain extender, is excellent in adhesive strength and stretchability, And a short curing time, and a process for producing the same.

In order to achieve the above object, the present invention provides a highly adhesive and highly elastic moisture curable reactive polyurethane hot melt adhesive composition comprising 13 to 32% by weight of a compound in which a polyester polyol having a molecular weight of 4000 to 6000 is modified with caprolactam, 19 to 40.5% by weight of a polyester polyol having a molecular weight of 2000 to 3000, 9 to 19% by weight of an isocyanate and 0.9 to 12.5% by weight of a chain extender.

In particular, the modified compound preferably has a molecular weight of 5,000 to 7,000 and OH VALUE of 50 to 150.

The polyester polyol may be selected from the group consisting of sebacic acid, adipic acid, sbelic acid, azelic acid, dodecanedioic acid and trimeric acid. Selected from among at least one carboxylic acid selected from the group consisting of ethylene glycol, diethylene glycol, butanediol, hexanediol, hexylene glycol, and trimethylol propane. Or a polyester polyol produced by reacting any one or more alcohols.

The polyurethane hot melt adhesive composition may also contain 0.5 to 1% by weight of a reactive defoamer.

The isocyanate is preferably selected from the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), tolunene diisocyanate (TDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane And may include at least one of dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), and triphenylmethane triisocyanate.

Particularly, the isocyanate is obtained by mixing 4,4'-diphenylmethane diisocyanate (MDI) with triphenylmethane triisocyanate in a ratio of 2: 1 to 1: 2 desirable.

The chain extender may be selected from the group consisting of ethylene glycol, diethylene glycol, butanediol, hexanediol, hexylene glycol, and trimethylol propane And may include at least one or more.

According to another embodiment of the present invention, there is provided a process for producing a high-adhesive and high-stretch moisture-curing reactive polyurethane hot-melt adhesive composition, comprising the steps of: mixing a polyester polyol having a molecular weight of 4000 to 6000 with caprolactam to produce an amidated compound; And 13 to 32% by weight of the modified compound, 19 to 40.5% by weight of a polyester polyol having a molecular weight of 2000 to 3000, 9 to 19% by weight of an isocyanate and 0.9 to 12.5% by weight of a chain extender.

In particular, the modified compound preferably has a molecular weight of 5,000 to 7,000 and OH VALUE of 50 to 150.

The polyurethane hot melt adhesive composition of the present invention is excellent in adhesion strength and stretchability, can control initial bonding time, and has a short curing time. Further, since the top sheet bonded by using it is excellent in smoothness, it can be used in various applications such as automobiles, fibers, and wood.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. As well as the fact that

Throughout this specification, when an element is referred to as "including" an element, it is understood that it may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Throughout this specification OH VALUE means the number of mg of KOH (mg KOH / g) necessary to neutralize the acetic acid bound to the acetyl compound obtained from 1 g of polyol, OH VALUE = (56100 x number of functional groups of polyol) / Molecular weight of the polyol).

Hereinafter, the highly adhesive and highly stretchable moisture curable reactive polyurethane hot melt adhesive composition of the present invention and a method for producing the same will be described in detail.

First, the highly adhesive and highly elastic moisture-curable reactive polyurethane hot-melt adhesive composition according to an embodiment of the present invention comprises a compound in which a polyester polyol having a molecular weight of 4000 to 6000 is modified with caprolactam, a polyester polyol having a molecular weight of 2000 to 3000 , Isocyanates and chain extenders.

Specifically, it comprises 13 to 32% by weight of a compound in which a polyester polyol having a molecular weight of 4000 to 6000 is modified with caprolactam, 19 to 40.5% by weight of a polyester polyol having a molecular weight of 2000 to 3000, 9 to 19% by weight of an isocyanate, 0.9 to 12.5% by weight.

The modified compound preferably has a molecular weight of 5,000 to 7,000 and OH VALUE of 50 to 150.

Polyester polyols are formed by the reaction of one or more polyfunctional carboxylic acids with one or more diols or triols. The polyester polyol may be selected from the group consisting of sebacic acid, adipic acid, sbelic acid, abelic acid, azelic acid, dodecandioic acid, Trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid and trimellaric acid, and ethylene glycol, diethylene glycol, butandediol, hexanediol, hexylene glycol, And trimethylol propane. The polyol may be a polyester polyol produced by reacting at least one alcohol selected from trimethylol propane. In the case of the highly adhesive and highly stretchable moisture curable reactive polyurethane hot melt adhesive composition according to the present invention, at least one carboxylic acid selected from the group consisting of sebacic acid and adipic acid is reacted with butanediol, And a polyester polyol OH value of 250 to 280 produced by reacting at least one alcohol selected from hexanediol and hexylene glycol.

The caprolactam is used for modifying a polyester polyol having a molecular weight of 4000 to 6000, and the amino group and the carboxyl group can be provided by opening the ring by hydrolysis. The caprolactam of the present invention is preferably included in the polyurethane hot melt adhesive composition in an amount of 5 to 20% by weight, more preferably 10 to 15% by weight.

The isocyanate may be selected from the group consisting of an aromatic isocyanate, an aliphatic isocyanate, and a cyclized aliphatic isocyanate. Specifically, the isocyanate compound may be at least one selected from the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), tolunene diisocyanate (TDI), hexamethylene diisocyanate (HDI) But are not limited to, dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), or mixtures thereof. In order to obtain a desirable adhesive strength, the isocyanate is preferably used in a ratio of 2: 1 to 1: 2 of 4,4'-diphenylmethane diisocyanate (MDI) and triphenylmethane triisocyanate It can be mixed.

The chain extender may be a compound containing a diol group or a triol group and may include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, 3-methyl-1,5-pentanediol, hexanediol, cyclohexanediol, hexylene glycol, neopentyl glycol (ethylene glycol) ), Trimethylol propane, or a mixture thereof, but is not limited thereto. In the case of the polyurethane hot melt adhesive composition according to the present invention, it is preferable to use an ethylene glycol, diethylene glycol, butanediol, hexanediol, hexylene glycol and trimethylol propane trimethylol propane), and the like.

It is also preferable that the chain extender is contained in the polyurethane hot melt adhesive composition in an amount of 0.9 to 12.5% by weight. Outside this range, the initial adhesion of the polyurethane hot melt adhesive may be lowered.

 In addition to the reactants described above, catalysts may be used to prepare the polyurethane hot melt adhesive compositions of the present invention. Examples of such catalysts include organometallic compounds, tertiary amines, and mixtures thereof. The organometallic compound may include tin diacetate, tin dioctoate, tin dilaurate or dibutyl dilaurate, and the tertiary amine catalyst may include triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N, N'-dimethylperazine or 2- (dimethylaminoethoxy) ethanol. The amount of the catalyst and the type of the catalyst according to the present invention can be appropriately controlled by the production process conditions such as the temperature of the reactor, the residence time, etc. Preferably, the catalyst is used in an amount of 10 to 1000 ppm based on the weight of the composition.

Further, in order to prepare the polyurethane hot melt adhesive composition of the present invention, one or more additives may be used in addition to the above-mentioned reactants. Examples of such additives include a reactive antifoaming agent, an antioxidant, a UV absorber, a UV stabilizer, a colorant, a moldability improver and the like.

The reactive antifoaming agent is added to inhibit foaming of the foam during the production of the polyurethane hot melt adhesive composition, and may be a silicone antifoaming agent, a polyether defoaming agent or a mixture thereof, but is not limited thereto. The reactive antifoaming agent is preferably contained in the polyurethane hot melt adhesive composition in an amount of 0.5 to 1% by weight. When the amount of the antifoaming agent is less than 0.5% by weight, bubbles may be formed. When the amount of the antifoaming agent is more than 1% by weight, the physical properties of the composition may change.

The UV absorber may be added to increase the durability of the adhesive to the substrate, such as, but not limited to, benzophenone, benzotriazole, or mixtures thereof. The UV absorber is preferably contained in the polyurethane hot melt adhesive composition in an amount of 0.3 to 1% by weight.

The UV stabilizer is added to maintain adhesion to the substrate for a substantial period of time, and may be a sterically hindered amine light stabilizer, but is not limited thereto. The UV stabilizer is preferably contained in the polyurethane hot melt adhesive composition in an amount of 0.3 to 1.5% by weight.

According to another embodiment of the present invention, there is provided a process for preparing a polyurethane hot melt adhesive composition comprising the steps of producing a modified compound by mixing a polyester polyol having a molecular weight of 4000 to 6000 with caprolactam, To about 3000 polyester polyol, isocyanate, and chain extender.

The step of producing the modified compound may include mixing polyester polyol having a molecular weight of 4000 to 6000 with caprolactam, heating the mixture at 180 ° C for 60 minutes, and cooling to 80 ° C or lower. The modified compound preferably has a molecular weight of 5,000 to 7,000 and OH VALUE of 50 to 150.

Next, the mixing step comprises mixing 13 to 32.5% by weight of the modified compound, 19 to 40.5% by weight of a polyester polyol having a molecular weight of 2000 to 3000, 9 to 19% by weight of an isocyanate and 0.9 to 12.5% .

The step of mixing the reactants may be carried out in a batch reactor at 100 ° C to 150 ° C, preferably at 120 ° C to 140 ° C.

In the step of preparing the polyurethane of the present invention, in addition to the above-mentioned reactants, a catalyst or one or more additives may be used.

Hereinafter, a highly adhesive and highly elastic moisture-curable reactive polyurethane hot-melt adhesive composition according to an embodiment of the present invention will be described, and the concrete actions and effects of the present invention will be described. However, it should be understood that the present invention is not limited thereto.

[ Manufacturing example ]

Polyurethane Hot melt  Preparation of adhesive composition

[Comparative Example 1]

300 g of a polyester polyol having a number average molecular weight of 3000, 390 g of a polyester polyol having a number average molecular weight of 2000 to 3000 and 100 g of 1,4-butanediol as a chain extender were placed in a four-necked flask and heated at 120 캜 for 60 minutes . After cooling to 60 ° C, 180 g of 4,4'-diphenylmethane diisocyanate (MDI) was added. Subsequently, 9 g of a defoaming agent was added, stirred for 10 minutes, vacuum-reduced (-760 mmHg) and degassed for 60 minutes to prepare a polyurethane hot-melt adhesive composition.

 [Comparative Example 2]

A polyurethane hot melt adhesive composition was prepared in the same manner as in Comparative Example 1, except that 300 g of a polyester polyol having a number average molecular weight of 3000 was replaced by 300 g of a polyester polyol having a number average molecular weight of 4,000.

[Comparative Example 3]

A polyurethane hot melt adhesive composition was prepared in the same manner as in Comparative Example 1, except that 300 g of a polyester polyol having a number average molecular weight of 3000 was replaced by 300 g of a polyester polyol having a number average molecular weight of 5000.

[Comparative Example 4]

A polyurethane hot melt adhesive composition was prepared in the same manner as in Comparative Example 1 except that 100 g of a polyester polyol having a number average molecular weight of 3000 was replaced by 100 g of caprolactam.

[Example 1]

200 g of a polyester polyol having a number average molecular weight of 4000 and 100 g of caprolactam were added to a four-necked flask, and 3 g of HBR and 1.5 g of KOH were added. After heating, when the temperature reached 180 캜, the polyester polyol was modified for 60 minutes. After cooling to 80 ° C or lower, 390 g of a polyester polyol having a number average molecular weight of 2000 to 3000 and 100 g of 1,4-butanediol as a chain extender were placed and 180 g of 4,4'-diphenylmethane diisocyanate (MDI) Respectively. Subsequently, 9 g of a defoaming agent was added, stirred for 10 minutes, vacuum-reduced (-760 mmHg) and degassed for 60 minutes to prepare a polyurethane hot melt adhesive composition.

[Example 2]

A polyurethane hot melt adhesive composition was prepared in the same manner as in Example 1, except that 200 g of a polyester polyol having a number average molecular weight of 5,000 and 100 g of caprolactam were added.

[Example 3]

A polyurethane hot melt adhesive composition was prepared in the same manner as in Example 1, except that 200 g of polyester polyol having a number average molecular weight of 6000 and 100 g of caprolactam were added.

[Example 4]

A polyurethane hot-melt adhesive composition was prepared in the same manner as in Example 1, except that 120 g of 4,4'-diphenylmethane diisocyanate (MDI) as isocyanate and 60 g of triphenylmethane triisocyanate were added.

[Example 5]

A polyurethane hot-melt adhesive composition was prepared in the same manner as in Example 1, except that 60 g of 4,4'-diphenylmethane diisocyanate (MDI) as isocyanate and 120 g of triphenylmethane triisocyanate were added

The components and contents used in Comparative Examples 1 to 4 and Examples 1 to 5 are shown in Table 1 below.

division Molecular Weight Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Example 4 Example 5 polyester
Polyol 3000 300 200 4000 300 200 200 200 5000 300 200 6000 200 Caprolactam 100 100 100 100 100 100 Polyester Polyol 2000 ~ 3000 390 390 390 390 390 390 390 390 390 4,4'-diphenylmethane
Diisocyanate (MDI) 180 180 180 180 180 180 180 120 60 Triphenylmethane
Triisocyanate 60 120 1,4-butanediol 100 100 100 100 100 100 100 100 100 Reactive antifoaming agent 9 9 9 9 9 9 9 9 9

                                                             (Unit: g)

[ Experimental Example 1 ]

Shear bond strength, elasticity measurement

In order to evaluate the physical properties of the polyurethane hot melt adhesive composition prepared in the above Production Example, the shear bond strength was measured according to the test method of ASTM D3163 and the elongation was measured according to the test method of ASTM D412. The experimental results are shown in Table 2 below.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Example 4 Example 5 Shear bond strength
(kg / cm2) 8 9 9 8 16 18 18 25 27 Elongation (%) 390 400 395 410 550 605 595 650 635

The results of Table 2 show that the examples of the present invention exhibit excellent adhesive strengths, and in particular, Examples 4 and 5 including triphenylmethane triisocyanate exhibit the best adhesive strength.

In addition, the elongation percentage was also increased in the case of the compositions of the examples in comparison with the comparative examples, indicating that the polyurethane hot-melt adhesive compositions according to the examples have better stretchability than the other compositions.

[ Experimental Example 2 ]

Drying time measurement

The polyurethane hot-melt adhesive composition of the present invention prepared in the above-mentioned Production Example was melted at 120 ° C, applied to artificial leather to a thickness of 3 mm, and then dried under conditions of 25 ° C and 50% relative humidity. When the fingertip was lightly applied to the above-mentioned polyurethane hot-melt adhesive composition, the time when the composition was not stuck on the fingertip was regarded as the touching time, while the time when the adhesive completely disappeared was regarded as the complete drying time, The drying time of the composition was measured. The experimental results are shown in Table 3 below.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Example 4 Example 5 Time to dry touch (hour) 3 3 4 3 2 One One 0.5 0.5 Drying time (hour) 24 24 25 24 17 9 8 7 5

As a result of the experiment, it was found that the polyurethane hot melt adhesive composition according to the embodiment of the present invention is faster than the composition of the comparative example in both the touch dry time and the complete dry time, . In particular, it can be seen that the compositions of Examples 4 and 5 containing triphenylmethane triisocyanate have a shorter drying time shortening effect than the other compositions.

[ Experimental Example 3 ]

MDI and Triphenylmethane Triisocyanate  Polyurethane according to content ratio Hot melt  Measurement of physical properties of adhesive composition

In order to measure the physical properties of the polyurethane hot melt adhesive composition according to the content ratio of 4,4'-diphenylmethane diisocyanate (MDI) and triphenylmethane triisocyanate, the following experiment was conducted. Comparative Examples 5 to 8 were prepared in the same manner as in Example 4, except that the amounts of 4,4'-diphenylmethane diisocyanate (MDI) and triphenylmethane triisocyanate were different. The components and contents used in Comparative Examples 5 to 8 and Examples 4 to 5 are shown in Table 4 below.

division Molecular Weight Comparative Example 5 Comparative Example 6 Example 4 Example 5 Comparative Example 7 Comparative Example 8 Polyester Polyol 4000 200 200 200 200 200 200 Caprolactam 100 100 100 100 100 100 Polyester Polyol 2000 ~ 3000 390 390 390 390 390 390 4,4'-diphenylmethane
Diisocyanate (MDI) 175 150 120 60 30 5 Triphenylmethane
Triisocyanate 5 30 60 120 150 175 1,4-butanediol 100 100 100 100 100 100 Reactive antifoaming agent 9 9 9 9 9 9

                                                         (Unit: g)

The physical properties of the polyurethane hot melt adhesive composition thus prepared were measured by the methods of Experimental Examples 1 and 2, and the results are shown in Table 5 below.

division Comparative Example 3 Comparative Example 4 Example 4 Example 5 Comparative Example 5 Comparative Example 6 Shear bond strength (kg / ㎠) 17 18.5 25 27 19 17 Elongation (%) 550 605 650 635 595 600 Time to dry touch (hour) 2 One 0.5 0.5 One 1.5 Drying time (hour) 12 9 7 5 8 9

The results of Table 5 show that the content ratio of 4,4'-diphenylmethane diisocyanate (MDI) and triphenylmethane triisocyanate affects the shear bond strength of the polyurethane hot melt adhesive composition, and 4,4'-diphenyl It can be seen that the polyurethane hot melt adhesive composition in which the content ratio of methane diisocyanate (MDI) and triphenylmethane triisocyanate is 2: 1 to 1: 2 has the best shear bond strength.

Claims (9)

13 to 32% by weight of a compound in which a polyester polyol having a molecular weight of 4000 to 6000 is modified with caprolactam; 19 to 40.5% by weight of a polyester polyol having a molecular weight of 2000 to 3000; 9 to 19% by weight of isocyanate; And 0.9 to 12.5 wt% of a chain extender,
The isocyanate is characterized in that 4,4'-diphenylmethane diisocyanate (MDI) and triphenylmethane triisocyanate are mixed in a ratio of 2: 1 to 1: 2 Wherein the polyurethane hot melt adhesive composition is a polyurethane hot melt adhesive composition. The polyurethane hotmelt adhesive composition according to claim 1, wherein the modified compound has a molecular weight of 5000 to 7000 and OH VALUE of 50 to 150. The method of claim 1, wherein the polyester polyol is selected from the group consisting of sebacic acid, adipic acid, sbelic acid, azelic acid, dodecanedioic acid, Trimellitic acid and trimellaric acid with at least one selected from the group consisting of ethylene glycol, diethylene glycol, butanediol, hexanediol, hexylene glycol and trimethylol propane. and trimethylol propane. The polyurethane hot-melt adhesive composition according to claim 1, wherein the polyester polyol is a polyester polyol produced by reacting at least one alcohol selected from trimethylol propane. The polyurethane hotmelt adhesive composition according to claim 1, comprising from 0.5 to 1% by weight of a reactive defoamer. The method of claim 1, wherein the isocyanate is selected from the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), tolunene diisocyanate (TDI), hexamethylene diisocyanate (HDI And at least one selected from the group consisting of dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), and triphenylmethane triisocyanate. Polyurethane hot melt adhesive composition. delete The method of claim 1, wherein the chain extender is selected from the group consisting of ethylene glycol, diethylene glycol, butanediol, hexanediol, hexylene glycol, and trimethylol propane, and mixtures thereof. The polyurethane hot-melt adhesive composition according to claim 1, Mixing a polyester polyol having a molecular weight of 4000 to 6000 with caprolactam to produce an amidated compound; And
13 to 32 wt% of the modified compound; 19 to 40.5% by weight of a polyester polyol having a molecular weight of 2000 to 3000; 9 to 19% by weight of isocyanate; And 0.9 to 12.5 wt% of a chain extender;
The isocyanate is characterized in that 4,4'-diphenylmethane diisocyanate (MDI) and triphenylmethane triisocyanate are mixed in a ratio of 2: 1 to 1: 2 Wherein the polyurethane hot melt adhesive composition is a polyurethane hot melt adhesive composition. The process for producing a polyurethane hot melt adhesive composition according to claim 8, wherein the modified compound has a molecular weight of 5000 to 7000 and an OH VALUE of 50 to 150.