KR20180041559A - A composition of hot melt film - Google Patents

Abstract

A composition of a reactive hot melt resin and a reactive hot melt film made of the resin to be realized in the present invention are composed of linear polyurethane, an isocyanate blocking agent of a polyfunctional group, a reaction catalyst, and a reaction retarder. The composition consists mainly of a polyurethane resin and the isocyanate blocking agent as a latent hardening agent. The composition comprises a catalyst for promoting reaction, the reaction retarder to ensure long-term storage, and a heat resistance enhancer (preferably, a nano-silica fine powder) capable of supporting adhesive force maintenance without being melted in conventional No Sew press work.

Description

A composition of a reactive hot melt resin and a reactive hot melt film made of the resin {A composition of hot melt film}

The present invention relates to a composition of a reactive hot-melt resin and a reactive hot-melt film made of the resin, and more particularly, to a reactive hot-melt film comprising a reactive hot- A composition of a hot-melt resin, and a reactive hot-melt film made of the resin.

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 heat deformation is possible is a very important factor in the selection of the hot melt, which is a factor determining the heat resistance of the final product. 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 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)

It is an object of the present invention to provide a composition of a reactive hot-melt resin which changes its thermal properties from thermoplastic to thermosetting after heat-press work to have excellent heat resistance and a reactive hot-melt film made of the resin.

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.

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 securing long-term shelf life and a conventional No- And a heat resistance enhancer (preferably, nanosilica) that has a performance capable of assisting in maintaining the adhesive strength without being melted when being melted at the time of 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 .

The present invention is characterized by a reactive hot melt film produced by coating a reactive release hot melt resin made of the above composition onto 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 as a main component a resin and an isocyanate blocking agent as a latent curing agent. Especially, in the conventional No Sew press work, (Preferably, nano silica) having a performance capable of imparting heat resistance to the base material.

The reactive hot-melt film produced by coating the reactive hot-melt resin of the present invention and the conventional release paper of the present invention with the resin of the present invention is thermoplastic before hot pressing and thermosetting after hot pressing, There is a characteristic that it does not melt.

Meanwhile, the types of isocyanate blocking agents used as main components in 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 type 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 promoting the curing reaction is used, the reaction becomes more rapid and is usually difficult to be stored 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 in order to bring about rapid reaction of the isocyanate blocking agent through a short time hot pressing process and it has been confirmed that the high temperature storability is greatly improved through the use of the reaction retarder. In addition, in the present invention, a heat resistance enhancer is used, which is used to help maintain adhesion without melting during the conventional No Sew press work. At this time, it is preferable to use nano silica as the heat resistance enhancer.

Meanwhile, in Table 2 below, the composition of the reactive hot-melt resin according to the present invention and the film and the verification method of the 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

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

Fabric used: polyester jacquard fabric

Heat press condition

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

Application: Mixing without heat resistance enhancer 1 ~ Mixing 7

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

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

Adhesion evaluation: All of the hot melt films use a thickness of 100 탆. After 1 day of heat press, cut into 1 inch width and evaluated by tensile testing machine.

Result: Compared to conventional thermoplastic hot melt film, compounding 3 to compounding 9 showed excellent adhesion.

Mixing without heat resistance enhancer When 1 to 7 were pressed under Condition 2 (existing No Sew press condition), the hot melt melted and penetrated into the fabric, resulting in a very low bonding strength of less than 1 kgf / cm.

2. Heat resistance test

Purpose of Test: When the reactive hot-melt film starts to react by hot pressing and the curing reaction occurs, the heat resistance of the resin is increased. To evaluate this, a 1 kg load was applied to one side of the fabric bonded in a high-temperature oven to evaluate the time of peeling.

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.

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

3. Temperature of flow beginning test

Purpose: To determine 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.

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

4. Viscosity

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.

RESULTS: Using the heat resistance enhancer, the viscosity at 130 ° C under the NO Sew condition could be greatly improved. As a result, excellent adhesion was ensured after NO sewing under the same conditions as the conventional thermoplastic polyurethane hot melt film.

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 are superior in adhesion, heat resistance and viscosity compared with the conventional thermoplastic polyurethane hot- 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, adhesive resin with melting point 45 to 55 ° C. Molecular weight measurement using GPC resulted in a weight average molecular weight of about 150,000. 130 degree viscosity is about 60,000 cps.

2. Water-dispersed polyurethane 2: Polyester-based polyurethane. Adhesive resin with melting point 45 ~ 55 ℃. Molecular weight measurement using GPC showed a weight average molecular weight of about 100,000. 130 degrees Viscosity less than 20,000 cps.

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

4. Catalyst: It is possible to use metal-based catalysts such as tin, titanium, and bismuth. However, in this experiment, bismuth is used which is fast and not regulated.

5. Delayed agent: 2,4-Pentanedione. It interacts with the metal catalyst and delays the catalytic activity at low temperature. Typical urethane reaction retardants are acid-based materials which can delay the initiation of urethane reaction at low temperatures, but they have the disadvantage of slowing the overall reaction rate even at high temperatures where appropriate reaction rates are required. 2,4-Pentanedione not only has excellent retardation at room temperature, but also has the advantage of restoring the activity of the metal-based catalyst sufficiently under no sewing conditions.

6. Heat Resistance Enhancer: Nano Silica. The aqueous polyurethanes 1 and 2 used had a viscosity lower than that of conventional thermoplastic hot melts at 130 ° C and 70 kgf, which is the conventional No Sew condition, so that when the No Sew operation is performed under the same conditions, the low viscosity can penetrate the material. And penetration may cause deterioration of the adhesive force. In order to prevent penetration, it is necessary to lower the temperature or pressure so that the convenience of use is significantly reduced. The nanosilica additive greatly improves the viscosity of the aqueous polyurethane resin at the No Sew temperature, allowing a sufficient amount of resin to remain at the interface of the material after no sewing. It can be immediately applied to No Sew under the same conditions as those of the conventional thermoplastic hot-melt resin, ensuring convenience. The size of the nanosilica used is about 5 to 50 nm.

Claims (3)

In the composition of the reactive hot-melt resin,
A composition of a reactive hot melt resin characterized by comprising a polyurethane resin, an isocyanate blocking agent, and a heat resistance enhancer
The method according to claim 1,
Wherein the heat resistance enhancer is nanosilica.
A reactive hot melt film produced by coating the release hot paper with the reactive hot melt resin according to any one of claims 1 and 2.