JP2886194B2 - Reactive hot melt film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a reactive hot melt film, and more particularly, to a combination of a latent curing system of a thermoplastic saturated polyester resin and a blocked polyisocyanate compound as active ingredients. Due to this, it exhibits excellent durable adhesive strength by ordinary thermocompression bonding means, and can be used effectively as an adhesive sheet (or film or tape) and also as an adhesive coating material by providing an appropriate base layer. Related to hot melt films.

Conventional technology and problems to be solved by the present invention Conventionally, a pressure-sensitive adhesive or an adhesive is previously applied to a base material such as a polymer film or a woven fabric, for example, an adhesive type such as a vinyl tape or a gum tape, or an applique bonded with an iron. Hot-melt adhesive type has been put to practical use. However, the adhesive type
No consideration is given to physical properties such as strength and elongation as a film or tape, and naturally high adhesive strength cannot be expected, and durability such as heat resistance is low. On the other hand, the hot-melt adhesive type has a difference in the hot-melt adhesive used, but has a limit in heat resistance.

Accordingly, the present inventors have conducted intensive studies to provide a hot-melt adhesive type film having sufficient film physical properties and exhibiting excellent durable adhesive strength such as heat resistance. For polyester resin,
By combining a blocked polyisocyanate compound in which a free isocyanate group is blocked, in a multi-layer film in which layers of each component are laminated, the blocked polyisocyanate compound is dissociated at the time of bonding by thermocompression bonding, and the It undergoes a curing reaction with the plastic saturated polyester resin, and due to such a latent curing system of both components,
They have found that an adhesive layer having higher heat resistance than before bonding can be formed, and have completed the present invention.

Configuration and effect of the invention That is, the present invention is formed by laminating a layer of a thermoplastic saturated polyester resin and a layer of a blocked polyisocyanate compound in which free isocyanate groups are blocked,
It is an object of the present invention to provide a reactive hot melt film characterized in that a thermoplastic saturated polyester resin is blended in the layer of the blocked polyisocyanate compound.

The thermoplastic saturated polyester resin (hereinafter, referred to as polyester resin) in the present invention refers to an aromatic dicarboxylic acid (terephthalic acid, isophthalic acid, phthalic anhydride, 2,6
-At least one of naphthalenedicarboxylic acid, trimellitic acid, paraoxybenzoic acid, etc.) and aliphatic dicarboxylic acids (such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanic acid, eicosaninic acid, ε-caprolactone) and glycols (Ethylene glycol,
Propanediol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, polyethylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, tri A random co-condensation polymer having a terminal OH group with at least one of methylolpropane and pentaerythritol, usually having a molecular weight of 5,000 to 50,000 and a softening point of 80 to 200 ° C.

The blocked polyisocyanate compound (hereinafter, referred to as a blocked NCO compound) in the present invention refers to a compound obtained by blocking a free isocyanate group of a polyisocyanate compound with a thermally dissociable compound according to a conventional method.

As the polyisocyanate compound, for example, 2,
4 / 2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, polyphenylmethane polyisocyanate called crude MDI, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane-4,
Aliphatic, alicyclic or aromatic di- or triisocyanate compounds such as 4'-diisocyanate and triphenylmethane triisocyanate, or these polyisocyanate compounds and low molecular weight glycol or triol (for example, dipropylene glycol, 6-hexanediol, 1,2,6-hexanetriol, trimethylolpropane) and the like.

Examples of the heat dissociable compound include ethanol,
Alcohols such as propane, butanol and isobutanol; phenols such as phenol, cresol, xylenol and p-nitrophenol; ethyl malonate;
Active methylene compounds such as ethyl acetoacetate and acetylacetone; acid amides such as acetamide, acrylamide and acetanilide; acid imides such as succinimide and maleic imide; 2-ethylimidazole;
Imidazoles such as ethyl-4-methylimidazole, lactams such as 2-pyrrolidone and ε-caprolactam, oximes of ketones or aldehydes such as acetoxime, methylethylketoxime, cyclohexanone oxime and acetoaldoxime, ethyleneimine, bisulfite and the like Lactams and oximes are preferable from the viewpoint of storage stability, curability and the like, and ε-caprolactam, methyl ethyl ketoxime and cyclohexanone oxime are particularly preferable. Such a heat dissociable compound is a polyisocyanate compound having its NC
Blocking may be performed at a ratio of about 0.9 to 1.5 equivalents (preferably 1 to 1.3 equivalents) per mole of O group.

The reactive hot melt film according to the present invention contains the polyester resin and the block NCO compound as active ingredients, specifically, a layer of a polyester resin (hereinafter, referred to as a polyester layer) and a layer of a block NCO compound (hereinafter, a block). A so-called multi-layer type of three layers, in which one polyester layer is interposed between two stacked NCO layers or two block NCO layers, is referred to as an example. Of course, the present invention is not limited to this, and it is also possible to combine the polyester layer and the block NCO layer into a multi-layer of four or five or more layers. A polyester resin (which may be the same or different from the one used for the polyester layer) is separately added to the block NCO layer, whereby the film properties of the polyester resin in the hot melt film are more reflected. In this case, the blending amount of the polyester resin with respect to the block NCO compound may be selected so that the molar ratio of NCO / OH is 10 to 50. On the other hand, in the polyester layer, a usual curing catalyst (for example, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacryl mercaptide, dimethyltin dichloride,
Dibutyltin malate) may be added, thereby increasing the curing speed and shortening the pressing time (note that addition to the block NCO layer is also conceivable, but the stability is deteriorated even at room temperature, which is not preferable).

The thickness of each layer is usually 0.01 to 0.5 m for the polyester layer
m, it may be set to 0.001 to 0.5 mm in the block NCO layer.

The reactive hot-melt film thus constituted can be used as it is as a heat-resistant adhesive sheet (or film or tape), but may further be used in a suitable base material layer such as a polymer film or sheet (generally having a softening point). By providing a commercially available polyester film, polyurethane film, polyvinyl chloride film, polyamide-based film, etc. at 150 ° C., preferably 200 ° C. or higher), woven or non-woven fabric (in this case, provided below the polyester layer), The strength of physical properties is increased, and at the same time, it can be used as an adhesive coating material. further,
From a practical viewpoint, a functional film can be obtained by using PVC leather, synthetic leather, genuine leather or fabric as the base layer.

The reactive photomelt film thus obtained is a treated steel plate having an electrodeposition coated surface, a painted surface, a galvanized surface, a woven or nonwoven fabric, a porous surface material such as wood, a urethane foam or a PVC foam. Forms,
It has excellent adhesion to PVC, plastics such as acrylic or polycarbonate. To bond the reactive hot melt film to the adherend as described above, a home iron, a home dryer, or an oven or a heat source such as a near-infrared heating device, a far-infrared heating device, or a ceramic heater is used. All that is needed is a suitable crimping system. That is, the polyester resin and the block NCO compound are melted and mixed by heating and pressing at a temperature higher than the melting temperature of the polyester resin, and the block NCO compound is further dissociated, and the NCO group reacts with the hydroxyl group of the polyester resin to cure and adhere. Complete. As the normal bonding conditions, heating by a heat source of 120 to 200 ° C. and pressure bonding time of about 1 to 5 minutes are required. By changing the amount and
It can be adjusted to lower the temperature to the melting temperature of the polyester resin and to shorten the pressing time.

 Next, the present invention will be described more specifically with reference to examples.

Example 1 (1) Film substrate layer polyurethane emulsion (manufactured by ICI, Neoretz XR
−9618, 40% solids (% by weight, the same applies hereinafter)) and 2.
Add 0% acrylic thickener (Experimental Rheology Modifier WXP-300, manufactured by Rohm and Haas) to reduce emulsion viscosity (20 ° C)
Set to 1000 cps.

This viscosity-adjusted polyurethane emulsion is uniformly applied on a release paper in a thickness of 0.25 mm, and is forcibly dried at 100 ° C. for 2 minutes to form a polyurethane film layer having a thickness of 0.1 mm (strength of 137 kg / c).
m ² , elongation 550%).

(2) Multi-layer reactive hot melt film polyester resin (Eritaire UE340 manufactured by Unitika)
0, molecular weight 25000, softening point 105 ° C) in methyl ethyl ketone (MEK) to make a 30% solution (viscosity 3000 cps / 20
° C). This solution is uniformly applied on the polyurethane film layer of the above (1) with a thickness of 0.33 mm, and is forcibly dried at 80 ° C. for 2 minutes to form a 0.1 mm thick polyester layer.

Next, isophorone diisocyanate blocked with methyl ethyl ketoxime (IPDI-B135, manufactured by Hyurs)
8, 65% solids, about 8% NCO content after dissociation) and the same weight of the same polyester resin (Eritaire UE3400)
The 30% MEK solution is mixed to give an isocyanate-excess mixture with an NCO / OH molar ratio of about 25 after dissociation. The mixture is uniformly applied on the polyester layer and dried to form a block NCO layer having a thickness of 0.02 mm.

The reactive hot melt film obtained as described above was heated and pressed against the coated steel sheet under the conditions shown in Table 1 below, and immediately or on the next day, the 90 ° peel strength (adhesive strength) was measured. The results are also shown in Table 1.

Example 2 100 g of polyvinyl chloride (PCH-12Z, manufactured by Kanegafuchi Chemical Co., Ltd.)
A plasticizer (2-ethylhexyl trimellitate) (60 g) and kerosene (10 g) were added and mixed, and then the polyvinyl chloride sol obtained by defoaming was uniformly coated on a release paper to a thickness of 0.1 mm.
After baking and drying at 2 ° C. for 2 minutes to form a polyvinyl chloride film layer having a thickness of 0.08 mm (strength: 180 kg / cm ² , elongation: 24%), polyester of 0.1 mm thickness was obtained in the same manner as in Example 1 / (2). A layer and a block NCO layer having a thickness of 0.02 mm are sequentially formed to obtain a multilayer reactive hot melt film. It was confirmed that this multilayer film also had the same degree of heat creep as in Example 1.

Example 3 A vinyl resin sheet (manufactured by Sunstar Giken Co., Ltd., Orcia) was coated with the polyester resin prepared in Example 1 / (2).
Apply MEK solution, then block NCO of Example 1 / (2)
To a mixed solution of the compound and the polyester resin, a mixed solution in which 3% of dibutyltin diacetate in terms of solid content is added as a catalyst is applied repeatedly to prepare a reactive hot-melt vinyl chloride leather. The reactive hot-melt vinyl chloride leather sheet thus obtained is heated to about 140 ° C. and pressed on a hard board by a vacuum forming machine for 30 seconds. After cooling, the initial adhesion was measured with a push-pull gauge, and as a result, it was 2.0 kg / 25 mm, and the adhesion the next day was 4.0 kg / 25 mm.

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Claims (5)

(57) [Claims] 1. A layer of a thermoplastic saturated polyester resin and a layer of a blocked polyisocyanate compound in which free isocyanate groups are blocked, wherein the layer of the blocked polyisocyanate compound is coated with a thermoplastic saturated polyester resin. A reactive hot melt film characterized by being blended. 2. The reactive hot melt film according to claim 1, wherein one thermoplastic saturated polyester resin layer is interposed between two blocked polyisocyanate compound layers, and these are laminated. 3. The reactive hot melt film according to claim 1, further comprising a base layer separately provided under the layer of the thermoplastic saturated polyester resin. 4. The reactive hot melt film according to claim 3, wherein the substrate layer is a polymer film or sheet, a woven fabric or a nonwoven fabric. 5. The reactive hot melt film according to claim 3, wherein the substrate layer is a functional type wherein the base material layer is PVC leather, synthetic leather, genuine leather or fabric.