JPS61225379A - Production of synthetic leather melt-cuttable with high-frequency welder - Google Patents

Abstract

PURPOSE:A synthetic leather cuttable with a high-frequency welder is obtained by forming on the releasing material, the surface layer of a specific resin mixture, the intermediate layer of foamed polyurethane, the adhesive intermediate layer and the back layer of polyvinyl chloride. CONSTITUTION:The objective synthetic leather which is cuttable and weldable by means of a high-frequency welder is produced by laminating on a releasing layer, 24-45g/m<2>, on the solid basis, of the surface layer consisting of a resin mixture containing a polyester-polyurethane and a vinyl chloride-vinyl acetate copolymer where the content of vinyl polymers is 20-50wt%, after drying, further laminating 100-500g/m<2>, on the solid basis, of a foaming polyurethane intermediate layer containing a polyether polyurethane, an organic hydrated crystal as a foaming agent where the content of polyester vehicle is 50%, then piling up to the resultant laminate, another laminate consisting of a releasing sheet, 215g/m<2>, on solid basis, of polyvinylchloride and an adhesive such as a polyamide adhesive on its back surface and peeling off the releasing sheets from the integrated laminate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing synthetic leather that can be welded and cut by high frequency welding.

(Prior art) In order to manufacture bags, bags, clothing, etc. using synthetic leather, methods such as sewing the periphery of synthetic leather cut into a predetermined shape with thread or gluing it with adhesive are used. However, it requires a lot of effort and the sewing and gluing parts do not look good.

As a solution to this problem, a method of welding and fusing using a high-frequency welder has been adopted.

Polyvinyl chloride is known as a resin suitable for high-frequency welders, but synthetic leather using polyvinyl chloride has a cold feel on the surface, is sticky, and has poor dimensional stability due to temperature changes.

In particular, it cannot be considered a luxury product because it has poor cold resistance and bending resistance and cracks occur on the surface in extremely cold weather. , synthetic leather with a foamed polyurethane layer on the base fabric is known, but when nylon fiber is used as the base fabric, the base fabric surfaces can be overlapped and welded using a high-frequency welder. Even if it were possible, it would not be possible to fuse it with a high-frequency Elder. Furthermore, the above-mentioned synthetic leather has the disadvantage that curling occurs when the foamed polyurethane layer has a large basis weight.

(Means for Solving the Problems) This invention uses a mixed resin of polyester polyurethane and a vinyl chloride/vinyl acetate copolymer (20 to 50% by weight of the vinyl copolymer in the mixed resin) as a mold release material. A surface layer made of polyvinyl chloride is provided, an intermediate layer of foamed polyurethane is provided on this surface layer, a back layer made of polyvinyl chloride is adhered to this intermediate layer via an adhesive, and then the mold release material is peeled off from the surface layer. This is a manufacturing method for synthetic leather that can be cut by high-frequency welding.

Before explaining this invention in detail, the structure of the synthetic leather obtained by this invention will be explained with reference to the drawings.
1 is a surface layer, 2 is an intermediate layer, 3 is an adhesive layer, and 4 is a back layer.

The resin forming the surface layer 1 of the synthetic leather is a mixed resin of polyester polyurethane and vinyl chloride/vinyl acetate copolymer (vinyl chloride content 85-99%), and the mixing ratio is vinyl to the total amount of the mixed resin. System copolymer is 20-5
It is 0% by weight. The vinyl copolymer in the mixed resin is 20%
If it is less than 50% by weight, the surface layer cannot be cut by a high frequency welder, and if it exceeds 50% by weight, the surface layer becomes hard.

In addition, cold resistance and folding resistance are reduced. The solid content of the surface layer is 24
-45g/rrl, preferably 30-33g/rrl.

If the solid content of the surface layer is less than 24 g/rrr, the desired grained state cannot be obtained. Moreover, if it exceeds 45 g/rf, the melt cutting by the high frequency welder cannot be performed properly, and small wrinkles cannot be obtained on the surface layer, resulting in poor appearance.

The foamed polyurethane that forms the intermediate layer 2 of the synthetic leather is a polyether polyurethane containing 50% organic crystal (hydrate).
% and a polyester vehicle, a tertiary amine derivative catalyst, a pigment, etc., are foamed by heating. The solid content of polyurethane foam is 100 to 500 g/rrr
, preferably 200-250 g/rrr.

When it is less than 100g/%, dense bubbles are difficult to generate,
Moreover, if it exceeds 500 g/%, the thickness of the intermediate layer will become non-uniform.

The polyvinyl chloride forming the back layer 4 of the synthetic leather is a conventionally known polyvinyl chloride, and is a composition containing a plasticizer, an inorganic filler, a stabilizer, a viscosity modifier, a pigment, etc. The solid content of this polyvinyl chloride composition is 200 to 500.
g/i, preferably 210 to 250 g1rd,
If it is less than 200 g/%, it becomes difficult to peel off when a release paper is also used for the back layer. If it exceeds 500g/I, it is unsuitable for use as an exterior material.

Adhesive layer 3 for bonding the intermediate layer 2 and back layer 4
has adhesive properties to both polyurethane foam and polyvinyl chloride, and uses an adhesive solution in which a polyamide resin is dissolved in a solvent.

The solid content of the adhesive is 2 to Log/rrr, preferably 3 to 6 g/rrr. If it is less than 2g/rrr, the plasticizer in the polyvinyl chloride of the back layer will migrate to the adhesive layer, resulting in a decrease in the adhesiveness of polyurethane foam, and if it exceeds 10g/rrr, the adhesiveness will improve. It's not something you can do.

To produce synthetic leather, the surface layer 1 and intermediate layer 2 are integrated by a transfer method. In other words, the mixed resin solution for the surface layer is applied to a release material such as polypropylene film or silicone-treated paper, and then dried.A foamed polyurethane solution for the intermediate layer is applied to this surface layer and dried. do. Further, in order to adhere the back layer to the intermediate layer formed on the mold release material, it is preferable to use the transfer method as described above. That is, a polyvinyl chloride composition that will become the back layer is applied to another mold release material, it becomes a gel by drying, an adhesive liquid is applied on top of this back layer, it is dried, and this adhesive layer is applied to the previous intermediate layer. After overlapping, they are pressed together, aged at an appropriate temperature to integrate, and then the mold release material is peeled off.

By using the transfer method as described above, the surface layer and the back layer have a smooth or uniform textured pattern, and the dimensional stability of each part is maintained during the manufacturing process. In addition, when bonding the back layer to the intermediate layer formed on the mold release material,
The back layer may be directly adhered to the intermediate layer via an adhesive liquid, without using a transfer method.

(Example) 70 parts by weight of polyester polyurethane (nonvolatile content 30%, 100% modulus 40 kg/ci) and vinyl chloride/vinyl acetate copolymer (vinyl chloride content 90%, average A mixed resin solution with a viscosity of 5,000 cps was prepared by dissolving 30 parts by weight of a resin with a degree of polymerization of 800) and 15 parts by weight of a pigment in a mixed solvent of 40 parts by weight of methyl ethyl ketone and 30 parts by weight of toluene.
It is coated at 0 g/m and dried at 90°C to form a surface layer. On this surface layer, polyether polyurethane 100
Parts by weight, organic crystal hydrate (50% polyester vehicle)
10 parts by weight of a foaming aid (contains), 1.
Viscosity: 23,000 cps, consisting of 2 parts by weight and 2 parts by weight of pigment.
The polyurethane composition was applied using a clearance coater to a solid content of 190 g/rrr, and dried and foamed at a temperature of 120° C. to form an intermediate layer. On the other hand, in a mold release material made of another polypropylene film, 100 parts by weight of polyvinyl chloride (average degree of polymerization 1650), 70 parts by weight of phthalic acid plasticizer (trade name PL200, manufactured by Mitsubishi Gas Chemical Co., Ltd.), and 10 parts by weight of calcium carbonate were added. , 2 parts by weight of viscosity modifier (trade name EC0N100, Zeon Corporation fI!i),
A plastisol composition (viscosity 5QQOcps) containing 4 parts by weight of Ba-Zn stabilizer and 8 parts by weight of pigment was applied to a solid content of 215 g/nf using a clearance coater, and the first chamber was heated at 140°C and the second chamber at 170°C. drying the plastisol composition by passing it through at a speed of 12 m/min;
It is gelled to form a back layer with a thickness of 0.2+m. Next, on this back layer, a polyamide adhesive was applied with methanol, toluene, and methyl ethyl ketone (mixing ratio: 40:
Dissolved in a mixed solvent of 40:20) and has a viscosity of 200 cpg.
Apply the adjusted adhesive liquid using a gravure roll coater to a solid content of 3.6 g/nf, and apply at a temperature of 120°C and a speed of 15 m.
/min to form an adhesive layer.

Next, while peeling off the release material on the back layer, the adhesive layer was superimposed on the intermediate layer made of foamed polyurethane, adhered with a nip pressure of 3 kg/ai and a roll clearance of 0.3 N, and further aged at 60°C for 1 hour. Thereafter, it was rolled back with the back layer as the front surface and aged at room temperature for 48 hours, and then the release agent on the surface layer was peeled off to obtain synthetic leather. The back layers of the synthetic leather were stacked together and placed on a Bakelite insulating plate (thickness 0.5 re), and energized for 4 seconds using a high-frequency welder having a mold with a width of 1.0 no.
Welding and fusing were performed. The blending ratios of the surface layer components and the results of the Takaoka welder test are shown in Table 1 below.6 Welding was measured according to JIS-6772.

The results of measuring the physical properties of the synthetic leather of Example 2 are shown in Table 2 below.

(Effects of the Invention) The synthetic leather obtained by the present invention can not only be welded using a high-frequency welder, but also be cut by melting. In addition, the surface layer of synthetic leather does not become sticky and has excellent cold resistance, bending strength, and chemical resistance. Therefore, it is easy to manufacture bags, bags, etc.

[Brief explanation of the drawing]

The drawing is a cross-sectional view of synthetic leather obtained by the present invention. 2: intermediate layer, 3: adhesive layer, 4: back layer. Patent applicant: Toyo Cross Co., Ltd. Agent: Patent Attorney Takeo Sakano Yoshi 1) Tsukasa

Claims (1)

[Scope of Claims] [1] The mold release material is provided with a surface layer made of a mixed resin of polyester polyurethane and vinyl chloride/vinyl acetate copolymer (20 to 50% by weight of vinyl copolymer in the mixed resin). , a high-frequency welder characterized in that an intermediate layer of foamed polyurethane is provided on this surface layer, a back layer made of polyvinyl chloride is adhered to this intermediate layer via an adhesive, and then a mold release material is peeled off from the surface layer. A method for producing synthetic leather that can be melted. [2] The method for producing synthetic leather that can be cut by high-frequency welding according to claim 1, wherein the vinyl chloride/vinyl acetate copolymer in the mixed resin of the surface layer has a vinyl chloride content of 85 to 99%. [3] The method for producing high-frequency welder-cuttable synthetic leather according to claim 1 or 2, wherein the foamed polyurethane of the intermediate layer is polyether polyurethane.