KR101915407B1 - A composition of hot melt film - Google Patents

Abstract

The composition of the reactive hot-melt resin to be implemented in the present invention and the reactive hot-melt film made of the resin are composed of a linear polyurethane, an isocyanate blocking agent of a polyfunctional group, a reaction catalyst, a reaction retarder and the like, A catalyst for accelerating the reaction, and a reaction retarder for securing long-term shelf life while using a resin and an isocyanate blocking agent as a latent curing agent as a main component.
Particularly, the composition of the reactive hot-melt resin according to the present invention can be used as a heat resistance enhancer that can achieve a performance capable of helping to maintain adhesive strength by eliminating the phenomenon that melts and collapses at the time of a conventional no- And further comprising nanosilica.

Description

A composition of hot melt film < RTI ID = 0.0 >

The present invention relates to a composition of a reactive hot-melt resin , and more particularly, to a composition of a reactive hot-melt resin capable of realizing excellent heat resistance by changing thermal properties from thermoplastic to thermosetting after a hot press operation.

As is well known, a hot melt film is a film having a thermoplastic property and is produced by coating a release paper with a hot melt resin. Such a hot-melt film adheres the adherend and the adherend. When the hot-melt film is placed between the adherend and heated and pressed, the hot-melt film sticks to the surface of the adherend while being dissolved by heat.

As the hot melt film used for such a purpose, a polymer material such as polyurethane, polyethylene, polyethylene vinyl acetate, polyester, polyamide is used as a typical example, and a liquid adhesive such as a solvent type adhesive or an aqueous adhesive is used, The process is simpler than the method of joining two fabrics through the process, and it is advantageous for process automation as well as being eco-friendly, so that it is widely used in various fields in recent years.

Since the hot-melt film as described above is mostly thermoplastic, it may be remelted if it is subjected to heat and pressure again after being adhered to the adherend by heating and pressing. This property has the advantage of being reworkable, but there is a concern that undesired thermal deformation may occur.

On the other hand, the temperature at which thermal deformation is possible is a very important factor in the selection of hot melt, which is a factor that determines the heat resistance of the final product. In this case, reactive hot melts may be used in addition to thermoplastic hot melts.

A conventional reactive hot melt uses a method in which a functional group capable of reacting with heat, humidity, etc. is left in the polymer structure, and the reaction proceeds gradually after application to the material and cures. Particularly, in the case of a polyurethane hot melt, the isocyanate functional group is left to be applied to the material, and then the material is cured by directly reacting with water or the material. However, such a reactive hot melt can not be produced in the form of a film, and there is a fundamental problem that the possibility of deterioration during storage is very great.

Open No. 10-2012-0081094 (the name of the invention: reactive hot-melt adhesive composition publication date: July 18, 2012) Registered Patent Publication No. 10-1075373 (Name of the invention: reactive polyurethane-urea hot melt adhesive) Date of issue: October 24, 2011 Disclosure of the Invention Problems to be Solved by the Invention Disclosure of the Invention Problems to be Solved by the Invention Disclosure of the Invention Problems to be Solved by the Invention Disclosure of the Invention Problems to be Solved by the Invention Disclosure of the Invention Problems to be Solved by the Invention Disclosure No. 10-2006-0049309 (Title of the Invention: System and Method for Manufacturing Reactive Hot-Melt Adhesive Published Date: May 18, 2006)

An object of the present invention is to provide a composition of a reactive hot-melt resin which is thermoplastic to thermoset and which has a thermal property changed to have excellent heat resistance.
Another object of the present invention is to provide a reactive hot-melt film which is easy to handle in the form of a film and excellent in long-term storage property by producing the reactive hot-melt film by coating the reactive hot-melt resin on a release paper.

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The composition of the reactive hot-melt resin according to the present invention comprises a polyurethane resin and an isocyanate blocking agent as a latent curing agent as main components, a catalyst for promoting the reaction therefrom, a reaction retarder for ensuring long-term storage stability, No Sew) is characterized by comprising a heat resistance enhancer (preferably, nanosilica) which has a performance capable of preventing adhesion of the adhesive strength by preventing the phenomenon of collapse during press work.

Preferably, the isocyanate blocking agent, which is a latent curing agent, is inactive under a typical storage condition of less than 40 ° C and does not react with polyurethane, exhibiting excellent storability, and is activated while being exposed to high temperatures during hot pressing to start the reaction .

Particularly, the present invention can improve the viscosity at a no sewing temperature by using a heat resistance enhancer (preferably, nano silica) so that a sufficient amount of the polyurethane resin can remain at the interface of the material after no- So that it can be prevented from being infiltrated into the work.

The present invention also has a technical feature of a reactive hot-melt film produced by coating a reactive hot-melt resin composed of such a composition (preferably an isocyanate blocking agent and nano-silica) on a conventional release paper.

The present invention is advantageous in that it has an excellent heat resistance due to a change in thermal properties from thermoplastic to thermosetting after a hot press operation and also has excellent shape stability and adhesion at high temperature as well as excellent hydrolysis resistance due to excellent heat resistance . Further, the present invention has the effect of exhibiting sufficient curing reaction even during a relatively short hot press working time due to the use of the reaction catalyst.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the following detailed description, exemplary embodiments of the present invention will be described in order to accomplish the above-mentioned technical problems. And other embodiments which may be presented by the present invention are replaced by descriptions in the constitution of the present invention.

The composition of the reactive hot-melt resin to be implemented in the present invention and the reactive hot-melt film made of the resin are composed of a linear polyurethane, an isocyanate blocking agent of a polyfunctional group, a reaction catalyst, a reaction retarder and the like, A catalyst for accelerating the reaction, and a reaction retarder for securing long-term shelf life while using a resin and an isocyanate blocking agent as a latent curing agent as a main component.

Particularly, the composition of the reactive hot-melt resin according to the present invention can be used as a heat resistance enhancer that can achieve a performance capable of helping to maintain adhesive strength by eliminating the phenomenon that melts and collapses at the time of a conventional no- And further comprising nanosilica.

The reactive hot-melt resin of the present invention, which is made of such a composition (specifically, an isocyanate blocking agent and nanosilica) and the resin of the present invention, which is prepared by coating the release paper with a conventional release paper, is thermoplastic before heat- And is characterized by being thermosetting after hot pressing, that is, not re-melting even after reheating after hot pressing.

Meanwhile, the types of isocyanate blocking agents used in the composition of the reactive hot-melt resin according to the present invention are shown in Table 1 below.

Kinds Dissociation temperature Melting point Boiling point Characteristic Methylethylketoxime (MEKO) 140-160 ° C -30 ° C 150 ℃ Used to adhere to hard adhesives like metal Dimethylpyrazole (DMP) 110 ~ 120 ℃ 218 ° C 218 ° C It is used to adhere to soft detergent like fabric and mainly used in water-soluble products Diethylmalonate (DEM) 100 to 120 ° C 199 ℃ 199 ℃ Disassociated at low temperature but easily dissociated when stored Diisopropylamine (DIPA) 140 to 150 ° C 249 ° C 249 ° C Caprolactam (E-CAP) 160 to 180 ° C 138 DEG C 138 DEG C

As shown in Table 1, the isocyanate blocking agent is activated at different temperatures depending on the type thereof. In the case of the MEKO type, a temperature of about 150 ° C. is required, which is used for a material stable at high temperatures. It can be activated around 110 ℃, so it can be used for material with weak heat. DMP (dimethylpyrazole) isocyanate blocking agents are the most suitable latent curing agents for materials with low heat resistance such as shoe materials.

The activation temperature of the isocyanate blocking agent refers to a temperature at which most dissociation occurs actively. At a temperature lower than 20 to 30 캜, dissociation starts to occur, which has a great influence on the storage stability of the final hot melt film. That is, when a hot-melt film prepared by coating a hot-melt resin prepared by using a DMP-type isocyanate blocking agent on a conventional release paper is stored at a high temperature of 50 ° C or higher for a long time, dissociation reaction and curing reaction progress gradually, It becomes impossible. In particular, when a catalyst for accelerating the curing reaction is used, the reaction proceeds more rapidly, which generally results in difficulty in storage for more than one day.

Therefore, in the present invention, a reaction retarder is used to improve the storage stability, and the reaction retarder is used together with the reaction catalyst to maximize the activity of the catalyst during storage to maximize the reaction between the isocyanate blocking agent and the polyurethane resin And is volatilized by itself under high temperature use conditions, thereby restoring the activity of the catalyst and promoting the reaction between the isocyanate blocking agent and the polyurethane resin.

On the other hand, the adhesive strength was improved by the hot press test on the fabric, as compared with the case where the isocyanate blocking agent was not used. This proves that the isocyanate blocking agent is activated in the hot press environment and the curing reaction proceeds with the polyurethane resin. It was confirmed that heat resistance was remarkably improved by the dead load test of the adhesive material compared with the resin not using the isocyanate blocking agent. In other words, it was confirmed that the thermoplastic resin changed into a thermosetting resin after the thermal press working. The role of the reaction catalyst is very important for the quick reaction of the isocyanate blocking agent through a short time hot pressing process and it has been confirmed that the high temperature storage stability is improved by using the reaction retarder.

Particularly, in the present invention, a heat resistance enhancer is used in producing a reactive hot-melt resin. This is to prevent adhesion of the adhesive layer to the adhesive layer, The viscosity at the no sewing temperature is greatly improved so that a sufficient amount of the polyurethane resin can remain on the boundary surface of the material after the non-sewing so as to prevent penetration of the material. At this time, it is preferable to use nano silica as the heat resistance enhancer.

On the other hand, in Table 2 below, the composition of the reactive hot-melt resin according to the present invention and a method for verifying a reactive hot-melt film produced by coating the resin on a conventional release paper are specifically shown.

TPU
Hot melt Formulation 1 Formulation 2 Formulation 3 Formulation 4 Formulation 5 Formulation 6 Formulation 7 Formulation 8 Formulation 9 Water-dispersed polyurethane 1




100
100
100
50
100
100 Water-dispersed polyurethane 2
100
100
100
50 DMP 2.5 5 10 5 5 5 5 catalyst One One One One One One One Retarder One One One One One One One Heat resistance
Enhancer 5 8 Adhesion (average, kgf / cm)
1.5
1.5
1.1
3
3.1
2.6
2.2
2.5
3.2
3.1 Heat resistance (sec) 55 <10 <6 45 44 47 15 25 82 95 Flow
Starting temperature (℃)
116
82
60
69
73
71
56
65
80
85 Viscosity
(cps @ 130 &lt; 0 &gt; C)
100,000
60,000
<20,000
50,000
40,000
30,000
<20,000
28,000
76,000
300,000

1. Adhesion test

end. Purpose: To evaluate the degree of improvement of adhesive strength compared to conventional thermoplastic polyurethane hotmelt.

I. Fabric used: polyester jacquard fabric

All. Heat press condition

(1) Condition 1: 35 kgf, 130 캜, 30 seconds (under a low-pressure press condition)

(2) Condition 2: 70 kgf, 130 캜, 30 seconds (existing No Sew press condition)

la. Application: Mixing without heat resistance enhancer 1 ~ Mixing 7

hemp. Application Formulation: Formulation 8 with Heat Resistance Enhancer, Formulation 9, Conventional TPU Hot Melt

bar. Adhesion Evaluation: All of the hot melt films were 100 탆 thick, and after 1 day of hot pressing, they were cut into 1 inch wide and evaluated by a tensile tester.

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four. Results: Compared with conventional thermoplastic hot melt films, compounding 3 to compounding 9 showed excellent adhesion. Further, when the compounding formulation 1 and 7 did not use a heat-resistant improving agents hayeoteul press in Condition 2 (No Sew existing press conditions) the hot melt is melted and penetrates the fabric came very low, the adhesive strength is less than 1kgf / cm.

2. Heat resistance test

end. The purpose of this test is to evaluate the heat resistance of the resin when the reactive hot-melt film starts to react with the hot press and the curing reaction takes place. To evaluate this, the time to peel off by applying a load of 1 kg to one side of the fabric adhered in a high- .

I. After cutting the fabric with 1 inch wide and 15 cm long, put 1 kg of weight on one end and put it in the oven at 130 ° C to measure the time of complete peeling.

All. Results: Formulations 8 and 9 showed better heat resistance than conventional thermoplastic polyurethane hotmelt.

3. Temperature of flow beginning test

end. Purpose: To determine the temperature at which a hot press can be made, measure the temperature at which the resin begins to flow while increasing the temperature at a constant load.

I. Use a capillary rheometer to measure the temperature at which the hot melt film begins to flow.

4. Viscosity

end. It is important to find a hot-melt film composition having a viscosity similar to that of a conventional thermoplastic polyurethane hot-melt film at a heat press temperature of 130 占 폚. This has the similar viscosity, so that the normal heat press condition can be used without change, which increases the usability.

I. RESULTS: Using the heat resistance enhancer, it was possible to greatly improve the viscosity at 130 ° C under no sewing condition. As a result, the adhesive strength after the no sewing under the same condition as that of the conventional thermoplastic polyurethane hot melt film Respectively.

On the other hand, in the case of a foam package commonly used as a shoe upper material (that is, a material having a fabric adhered to both sides of the foam: hereinafter referred to as a "foam package"), Shape, and it is given a certain pattern through punching process, etc., and is cut and used as a material such as a shoe upper. The most important part of this foam package material is the breathability of the foam package material itself bonded to the fabric and the adhesion to the fabric. In the case of foam packaging materials using conventional thermoplastic hot melt films, no ventilation is imparted, and foam packaging materials adhered to both sides of the 3D embossing surface required in shoe design are subjected to no sewing (no sewing) No Sew) Immediately after the press, a 3D embossing effect may be obtained, but if the No Sew press is repeated to bond a logo or other pattern on the foam package material, the thermoplastic hot melt film is melted again, There is a disadvantage that it disappears.

In order to solve such a problem, conventionally, polyurethane reactive (hereinafter referred to as " PUR "), which is a moisture-curable polyurethane hot melt resin, is used as a raw material or a roll There is a case that the moisture-curing resin is not stable in use and it is difficult to achieve a 3D effect.

In order to solve the problems of the prior art, in the present invention, the reactive hot-melt resin is not directly formed into a film, but is directly coated on the fabric with the resin alone and then subjected to the second-stage non-sewing press. The present invention is advantageous in that a fabric coated with a resin is adhered to a foam without using a film to have a breathability. In the case of a No Sew press bonding, an isocyanate blocking agent contained in a reactive hot- It is possible to maintain the 3D embossing effect by having the properties of the thermosetting resin which is not melted again in various subsequent processes.

Further, due to the heat resistance enhancer used for the reactive hot-melt resin, preferably nanosilica, the resin penetrates into the fabric and the foam even at a high pressure (30 kgf or more) during the No Sew press bonding, And it was confirmed that they had excellent adhesion. Tables 3 and 4 below show specific test verifications related to this.

Conventional technology
- 3D embo that remelted and released - Invention
- 3D Embo surviving vividly -

As shown in the photograph of Table 3, when a conventional polyurethane hot melt film or polyurethane hot melt resin is used, the film is remelted when the No Sew press operation is repeated, or the use of the wet cured resin The stability was not good and 3D effect could not be realized in the end. However, by using nano silica as a heat resistance enhancer in the production of a reactive hot-melt resin as in the present invention, the 3D embossing can be realized clearly as shown in the photograph.

TPU hot melt PUR hot melt Formulation 5 Formulation 6 Formulation 8 Formulation 9 Water-dispersed polyurethane 1

100

100 100 100 100 Water-dispersed polyurethane 2 100 DMP 10 5 5 5 catalyst One One One One Retarder One One One One Heat resistance enhancer 5 8 Heat resistance (sec) 55 <10 47 15 82 95 Flow starting temperature (캜) 116 74 71 56 80 85 Viscosity (cps @ 130 ℃) 100,000 10,000 30,000 <20,000 76,000 300,000 Thickness (㎛) 50 30 30 30 30 30 Ventilation No ventilation Ventilation Ventilation Ventilation Ventilation Ventilation 3D embossing (just after no sew press) Good No Molding Good Good Good Good 3D embossing (after 2,3 no sew press) no effect No Molding Good Good Good Good Adhesive strength (kgf / cm) 0.8 1.2 0.7 0.9 3.1 3.8

In order to demonstrate the physical properties of the composition of the reactive hot-melt resin of the present invention shown in Table 4, preferably when the reactive hot melt resin is prepared, the physical properties of the thermosensitive material (i.e., nanosilica) Specific verification methods and test result values for identifying the characteristics are as follows.

1. Adhesion test

end. Test purpose: To evaluate the degree of improvement in adhesion relative to conventional thermoplastic polyurethane hotmelt.

I. Fabric used: Polyester fabric and PU foam (front and back)

All. Heat press condition: 60 kgf, 130 캜, 30 seconds

la. Application formulations: see Table 4 above

hemp. Adhesion Evaluation: All of the hot melt films were 50 탆 thick, and after 1 day of hot pressing, they were cut into 1 inch wide and evaluated by a tensile tester.

Results: Compared to conventional thermoplastic hot melt film and PUR hot melt adhesive, compounding 8 to compound 9 showed excellent adhesion. At this time, when Compound 5 and Compound 6 without the use of the heat resistance enhancer were pressed, the hot melt melted and penetrated into the fabric, resulting in a very low adhesive strength of less than 1 kgf / cm.

2. Heat resistance test

end. Purpose of Test: When a reactive hot melt film starts to react with a hot press to cause a curing reaction, the heat resistance of the resin is increased. In order to evaluate this, a time of peeling was evaluated by applying a load of 1 kg to one side of the bonded fabric in a high-temperature oven.

I. The heat-pressed fabric was cut to a width of 1 cm and a length of 15 cm. Then, a weight of 1 kg was hung on one end and put in an oven at 130 ° C to measure the time of complete peeling.

All. Results: Formulations 8 and 9 showed better heat resistance than conventional thermoplastic polyurethane hotmelt.

3. Temperature of beginning test

end. Purpose: To measure the temperature at which hot press is possible, measure the temperature at which the resin begins to flow by increasing the temperature at a constant load.

I. Use a capillary rheometer to measure the temperature at which the hot melt film begins to flow.

4. Viscosity

end. It is important to find a hot-melt film composition having a viscosity similar to that of a conventional thermoplastic polyurethane hot-melt film at a typical hot-press temperature of 130 ° C. This has the similar viscosity, so that the normal heat press condition can be used without change, which increases the usability.

I. RESULTS: Using the heat resistance enhancer, it was possible to greatly improve the viscosity at 130 ° C under no sewing condition. As a result, the adhesive strength after the no sewing under the same condition as that of the conventional thermoplastic polyurethane hot melt film Respectively.

As described above, the reactive hot-melt resin according to the present invention and the reactive hot-melt film produced by coating the resin on a conventional release paper have adhesive strength, heat resistance, heat resistance, and heat resistance as compared with the conventional thermoplastic polyurethane hot melt film or polyurethane reactive (PUR) Viscosity and the like, and the composition and the role of the composition of the present invention will be described in detail below.

1. Water-dispersed polyurethane 1: Polyester-based polyurethane having a melting point of 45 to 55 ° C as an adhesive resin and having a weight average molecular weight of about 150,000 as measured by GPC, 60,000 cps.

2. Water-dispersed polyurethane 2: Polyester-based polyurethane having a melting point of 45 to 55 ° C as an adhesive resin and having a weight average molecular weight of about 100,000, a viscosity of 130 ° C Less than 20,000 cps.

3. DMP Block Potential Hardener: HDI trimer, IPDI trimer, dimethylacrylate block, isocyanate group.

4. Catalyst: It is possible to use metal-based catalysts such as tin, titanium, and bismuth. However, in this experiment, a bismuth system is used which has a high reaction rate and is not regulated.
5. Reaction retardant : 2,4-pentanedione . The reaction of the catalyst with the metal catalyst is delayed and catalytic activity at low temperature is delayed. The urethane reaction retardant is an acid-based material and can delay the initiation of the urethane reaction at low temperature. However, even at a high reaction temperature, There is a drawback to slowing down. The 2,4-pentanedione has an advantage of being excellent in the retardation performance at room temperature and sufficiently restoring the activity of the metal-based catalyst under no -saw condition.

6. Heat resistance enhancer: It is preferable to use nano silica. The aqueous polyurethane 1 and the aqueous polyurethane 2 used have viscosity lower than conventional thermoplastic hot melts at 130 ° C. and 70 kgf, which is a no sew condition, If no sewing is performed under conditions, the material may be infiltrated due to low viscosity. Such penetration may cause deterioration of adhesive strength, and in order to prevent over-penetration, the temperature and pressure must be lowered so that the convenience of use is significantly reduced. The nanosilica additive of the present invention greatly improves the viscosity of the aqueous polyurethane resin at the No Sew temperature and allows a sufficient amount of resin to remain on the interface of the material after no sewing. It can be immediately applied to the non-sewing (No Sew) under the same conditions as those of the conventional thermoplastic hot-melt resin, thereby ensuring convenience. The size of the nanosilica used as the heat resistant promoter in the present invention is preferably about 5 to 50 nm.

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Claims (4)

In the composition of the reactive hot-melt resin,
Polyurethane resin ;
A DMP (dimethylpyrazole, dimethylpyrazole) type isocyanate blocking agent ;
2,4-pentanedione ;
The composition of claim 1, wherein the reactive hot-melt resin comprises nano-silica . delete delete delete