JPH0376668B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses a relatively flexible cover made of cloth, leather, synthetic resin sheets, or laminated sheets thereof to impart appropriate shape retention and elasticity to shoes manufactured by injection molding, vulcanization, etc. The present invention relates to a shape-retaining sheet material for shoes that has improved attachment properties to shoelaces in the shoe manufacturing process. Conventionally, when manufacturing shoes by attaching a shape-retaining sheet material such as a heel core to a shoe made of cloth, leather, synthetic resin sheets, or laminated sheets of these, rubber, thermoplastic elastomer, polyethylene, Thermoplastic resin sheets such as polypropylene, ethylene-vinyl acetate copolymer, ionomer, etc., leather boards, styrene-containing nonwoven fabrics, etc. are used, and these are laminated and heated directly with the cover, or attached using a solvent-based adhesive. was. However, this mounting method has drawbacks. In other words, when the shape-retaining sheet material and the cover are laminated and heated as they are, depending on the shape-retaining sheet material, there may be almost no adhesion, or a high temperature may be required to obtain sufficient adhesion. Quality deteriorates and productivity also decreases. Furthermore, when attaching with a solvent-based adhesive, it pollutes the working environment and poses a problem in terms of labor safety. From this point of view, shape-retaining sheet materials that can be attached with low-temperature adhesive properties to prevent deterioration in the quality of the skin during attachment and improve productivity, and non-solvent adhesives to prevent environmental pollution, are strongly sought after. ing. Shape-retaining sheet materials are required to have bending resistance, shoe shape-retaining properties, low-temperature moldability, appropriate flexibility, water resistance, etc. Ethylene copolymers, especially ionomer resins, are suitable for these materials. The resin sheet coated with a hot melt adhesive based on ethylene-ethylenically unsaturated ester copolymers such as polyamide, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylic acid ester copolymer, etc. is widely used. I'm getting used to it. However, although polyamide-based hot melt adhesives have good adhesion with ionomer resins, the activation temperature of the polyamide is high, so it is necessary to raise the molding temperature during the shoe manufacturing process to attach the shoelaces and the shape-retaining sheet material. It also has the drawbacks of causing deterioration of the quality of the molding material, poor molding cycles, and reduced productivity. Ethylene-ethylenically unsaturated ester copolymer hot melt adhesives improve the above-mentioned drawbacks, but lack adhesion to ionomer resin sheets. That is, since the hot melt adhesive has a low viscosity, it is necessary to coat it by a roll coating method, and this method has poor adhesion to the ionomer resin sheet. For this reason, there is a drawback that it causes inconvenience in the process of adhering to the skin. In view of these drawbacks of conventional shape-retaining sheet materials, the present invention relates to a shape-retaining sheet material that can be molded at low temperatures and has good adhesion to laces. As a result of intensive research, the present inventor has made use of the features of ethylene-ethylenically unsaturated ester copolymer hot melt adhesives to improve the roll coating adhesive strength between them and ionomer resin sheets.
In between these resin layers are (a) 20 to 60% by weight of a low-crystalline or non-crystalline ethylene-α-olefin copolymer having a density of 0.85 to 0.90, and (b) ethylene-ethylenically unsaturated ester copolymer. Combined 20-60% by weight, (c)
This objective could be achieved by interposing a resin composition layer formed by uniformly mixing 10 to 30% by weight of a tackifier. That is, the present invention provides an ethylene-ethylenically unsaturated ester copolymer-based hot melt layer A/(a) a low-crystalline or non-crystalline ethylene-α-olefin copolymer, (b) an ethylene-ethylenically unsaturated ester copolymer. , (c) a resin composition layer (B) consisting of a tackifier/an ionomer resin layer (C);
This relates to a laminated shape-retaining sheet material consisting of B/C or A/B/C/B/A, and by using this laminate as a shape-retaining material sheet, the low-temperature adhesion to the bark is improved. This made it possible to make shoes at low temperatures, improve the molding cycle, and prevent deterioration of the shoelaces due to thermal bonding. The ethylene-ethylenically unsaturated ester copolymer hot melt layer (A) used in the present invention includes:
Ethylene/vinyl acetate copolymer, ethylene/acrylic acid ethyl ester copolymer, etc. are suitable;
The copolymerized amount of these ethylenically unsaturated ester monomers is preferably in the range of 5 to 40% by weight. That is, if the content is less than the above range, it will be difficult to adhere to the skin, and if it is more than the above range, the blocking property of the shape retaining material sheet will be severe, making it difficult to handle the sheet during work. In both respects, results inferior to those within the scope of the present invention are obtained. The ethylene copolymer hot melt used may be blended with waxes and/or a caking agent, if necessary. The resin composition used for the intermediate layer (B) has (a) a density of 0.85 to
Low crystalline or amorphous ethylene α with 0.90
- A melt made by uniformly melting and mixing 20 to 60% by weight of an olefin copolymer, (b) 60 to 20% by weight of an ethylene-ethylenically unsaturated ester copolymer, and (c) 10 to 30% by weight of a tackifier. It is a resin composition having an index of 1 to 30 g/10 minutes. In the ethylene/α-olefin copolymer used as component (a) above,
α-offine is preferably propylene or butene-1, and its density is between 0.85 and 0.90 g/cm ³ and is low crystallinity (crystallinity of about 35% or less by specific volume method) or non-crystalline. or butene-1
is generally copolymerized in the copolymer at a proportion of about 5 to 50 mol%, preferably about 8 to 40 mol%, and its melt index may be in the range of about 0.2 to 3.0 g/10 min. preferable. The ethylene-ethylenically unsaturated ester copolymer used as component (b) is an ethylene/α,β-unsaturated carboxylic acid ester copolymer or an ethylene-vinyl ester copolymer and is produced by high-pressure radical polymerization. be done. Examples of α,β-unsaturated carboxylic acid esters include methyl, ethyl, n-butyl, and isobutyl esters of acrylic acid or methacrylic acid, preferably acrylic acid ethyl ester, and vinyl esters include, for example. Vinyl acetate, vinyl propionate, etc. are used,
These are preferably copolymerized in a proportion of about 5 to 30% by weight in the copolymer. The tackifier used as component (c) is:
Aliphatic hydrocarbon resin, alicyclic hydrocarbon resin,
Examples include aromatic hydrocarbon resins, polyterpene resins, rosins, and styrene resins. Examples of aliphatic hydrocarbon resins include butene-
1, isoptylene, butadiene, 1,3-pentadiene, and other _C4 to _C5 mono- or diolefin-based polymers. Examples of alicyclic hydrocarbon resins include resins obtained by cyclizing and dimerizing diene components in spent C ₄ -C ₅ fractions, resins obtained by polymerizing cyclic monomers such as cyclopentadiene, and aromatic resins. Examples include resins obtained by intranuclear hydrogenation of hydrocarbon resins. Examples of aromatic hydrocarbon resins include vinyltoluene, indene, α
- Resins containing _C9 vinyl aromatic hydrocarbons such as methylstyrene as a main component. Examples of polyterpene resins include α-pinene polymer,
Examples include β-pinene polymer, dipentene polymer, terpene-phenol copolymer, α-pinene-phenol copolymer, and the like. Examples of rosins include rosin, polymerized rosin, water-soluble rosin, rosin glycerin ester and its aqueous solution or polymer, rosin pentaerythritol ester and its aqueous solution or polymer, and the like. Examples of styrene resins include styrene monomer polymers, styrene-olefin copolymers,
Examples include vinyltoluene-α-methylstyrene copolymer. Among these various tackifiers, aliphatic hydrocarbon resins and alicyclic hydrocarbon resins are particularly preferred from the viewpoint of color tone, odor, and the like. In the resin composition consisting of these components (a), (b) and (c), component (a) is about 20 to 60% by weight,
Component (b) is about 20-60% by weight, and component (c) is about 10-60% by weight.
It is used in a mixture of 30% by weight. Component (a) is 20% by weight or less, or component (b) is 80% by weight
With the above, there is a problem in coextrusion moldability with the ionomer resin, and therefore the adhesiveness with the ionomer resin layer is poor. Moreover, if the content of component (a) is 80% by weight or more, or the content of component (b) is less than 20% by weight, there will be difficulty in hot melt coating of the ethylene-ethylenically unsaturated ester copolymer hotmelt, resulting in a lack of adhesion. If the amount of component (c) exceeds the range of 10 to 30% by weight, the adhesiveness deteriorates, which is undesirable. The resin composition is prepared by mixing the above components simultaneously or sequentially. As for the mixing method, it is preferable to use a single screw extruder, twin screw extruder, Banbury mixer, various kneaders, etc. to uniformly melt and mix the components, and there is no particular restriction on the mixing order. The melt-mixed resin composition is
It is preferred to have a melt index in the range of about 1-30 (190°C). If the melt index is less than about 1, the viscosity of the resin will be too high, increasing the resin pressure and increasing the load on the motor, which will make extrusion moldability difficult, and will also affect the spreadability of the molten film that comes out of the die. cause problems. On the other hand, when the melt index is about 30 or more, coextrusion becomes difficult. The ionomer resin used for the ionomer resin layer (c) is a copolymer of ethylene and α,β-unsaturated carboxylic acid that has been neutralized with various metal ions. Specific examples include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and maleic anhydride. The content of these unsaturated carboxylic acid monomers is preferably 1 to 25 mol%.
Metal ions used for neutralization include Na ⁺ , K ⁺ ,
Li ⁺ , Cu ⁺⁺ , Ca ⁺⁺ , Mg ⁺⁺ , Be ⁺⁺ , Sn ⁺⁺ , Fe ⁺⁺ ,
Co ⁺⁺ , Zn ⁺⁺ , Al ⁺⁺⁺ , Fe ⁺⁺⁺ , etc. There are no particular restrictions on the degree of neutralization, but the melt index after neutralization with metal ions is in the range of 0.1 to 10. Preferably. If necessary, pigments, dry wood flour, and other resins such as low-density polyethylene, high-density polyethylene, polypropylene, etc. may be added to the ionomer resin as long as it does not impair the physical properties of the ionomer resin as a shape-retaining sheet material. I do not care. In the present invention, the resin composition (B) is molded into a sheet by an in-die adhesion method in which the ionomer resin (c) and the melted resin of the resin composition (B) are combined and laminated inside the die. Laminated by a general co-extrusion molding method such as an extrusion molding method, or a co-extrusion molding method using an outside-die adhesion method in which two or more resin molten webs are extruded from a flat die with two or more slits and then laminated. It is obtained by roll coating a sheet with an ethylene-ethylenically unsaturated ester copolymer hot melt. The thickness of the ionomer resin layer varies depending on the part of the shoe used as the shape-retaining material sheet, but for example, it is used in the range of 0.1 to 0.5 mm for the toe area and 0.5 to 2.0 mm for the heel counter (stiffener). be done. Further, the thickness of the intermediate layer is approximately 30 microns, and the thickness of the hot melt layer is approximately 0.1 mm. The sheet of the present invention has excellent attachability to shoelaces and is suitably used as a shape-retaining sheet for shoes.
It can be used not only for shoe making but also for any purpose requiring shape retention. Examples of the present invention will be described below. This example is not intended to limit the invention. Example 1 Ionomer resin having an MI of 2.5 g/10 minutes and a density of 0.95 g/cm ³ (Mitsui Polychemical's "Himilan"
30 parts (weight, same below) of ethylene-vinyl acetate copolymer (vinyl acetate content 6% by weight, MI7g/10 min), low crystalline ethylene-butene copolymer (butene-1 content 10%) on both sides of ^"R 1605". mol%), density 0.88
g/cm ³ , MI4 g/10 min) 50 parts and an aliphatic hydrocarbon resin as a tackifier (ring and ball softening point 115)
A resin composition having an MI of 2.8 g/10 minutes and a density of 0.94 g/cm ³ , which was prepared by melt-mixing 20 parts of oleic acid amide (0.2 parts of oleic acid amide), was coextruded by an outside-die adhesion method. In this case, the extruder temperature is 165 at the T-die exit.
℃, and the thickness of the molded sheet was 1.4 mm, of which the thickness of the ionomer resin layer was 1.34 mm. This sheet was coated with Mitsui Polychemical's "Evaflex ^R 40" 10.3% (weight, same below) and "Evaflex ^R 260" made by Mitsui Polychemicals using a roll coater.
An ethylene-vinyl acetate copolymer hot melt adhesive (180℃ viscosity 80,000 cps, ring and ball method softening point 70℃) containing 48.7% and ester gum 35% was coated at a coating temperature of 150℃ with a thickness of 0.1 mm on one side. It was applied to both sides of the sheet. The adhesive strength between this sheet and various shoe base materials is shown in Table 1 along with comparative examples. Comparative Example A sheet was molded using the same materials as in Example 1 except that the resin composition laminated on both sides of the ionomer resin layer was not used.

[Table] Test method: Seal bar temperature 120℃, pressure 3Kg/cm ² , time 30
Various shoe base materials and sample sheets were heat-sealed for 60 seconds, and the adhesive strength was measured after leaving them for one day. (180°
Peeling, tensile speed 300 mm/min n=3).

Claims (1)

[Scope of Claims] 1. The following (a) is provided between the ionomer resin layer and the ethylene-ethylenically unsaturated ester copolymer layer.
A thermoplastic resin laminate with a resin composition layer containing (b) and (c) as main components. (a) 20-60% by weight of a low-crystalline or non-crystalline ethylene/α-olefin copolymer having a density of 0.85-0.90 (b) 20-60% by weight of an ethylene-ethylenic unsaturated ester copolymer (c) Tackifier 10-30% by weight. 2 In ethylene/α-olefin copolymer-
The ethylene/αa-olefin copolymer according to claim 1, wherein the olefin is propylene or butene-1. 3. The ethylene-ethylenically unsaturated ester copolymer according to claim 1, wherein the ethylenically unsaturated ester is vinyl acetate. 4. The ethylene-ethylenically unsaturated ester copolymer according to claim 1, having a vinyl acetate monomer content of 5 to 30% by weight. 5. The ethylene-ethylenically unsaturated ester copolymer according to claim 1, wherein the ethylenically unsaturated ester is acrylic acid ethyl ester. 6 Acrylic acid ethyl ester monomer content is 5~
30% by weight of the ethylene-ethylenically unsaturated ester copolymer according to claim 1. 7. The laminate according to claim 1, wherein the thermoplastic resin laminate is a shape-retaining sheet material for shoes.