JPH0245983B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for simultaneously producing a release sheet and a thermoplastic elastomer film by coextrusion. Furthermore, the obtained laminate is characterized by excellent suitability for post-processing such as printing and bonding with various base materials. Elastomers, typically polyurethane, have traditionally been widely used in waterproof clothing, furniture, etc. by bonding them with cloth or non-woven fabrics due to their flexibility and abrasion resistance.The manufacturing method is to directly apply a polyurethane solution to cloth, etc. There are two main types of methods: the direct coating method, in which a polyurethane layer is first formed on a release paper, and the transfer method, in which the polyurethane layer is transferred to cloth or the like. The advantage of the transfer method over the direct coating method is that the polyurethane layer can be given a design such as printing or aluminum vapor deposition before transfer, which increases the added value after transfer and expands the range of uses. It can minimize the penetration of polyurethane into porous materials such as cloth,
It takes advantage of the texture of the material and requires less polyurethane. It may also be possible to process rough cloth and non-woven materials. Generally, the polyurethane layer used in the transfer method is prepared by coating a release paper with a reactive urethane solution consisting of a solution of linear polyurethane resin in an organic solvent, a urethane prepolymer with a terminal OH group, and an isocyanate curing agent. Obtained as ~30μ thick. The release paper used here is mainly kraft paper laminated with polyethylene or polypropylene, or silicone coated on top of that, and other types of release paper are those that are coated with silicone, and other types of release paper are those that are coated with silicone, and other types of release paper are those that are coated with silicone directly on smooth and less permeable papers such as glassine paper and parchment paper. There are those coated with a plastic film base material such as polyester and polypropylene that are subjected to a release treatment. As described above, in the conventional transfer method of elastomer such as urethane, the transfer paper is manufactured by applying a solution of elastomer such as urethane after performing a peeling treatment on the paper or plastic film in advance, so there are many processing steps. In particular, the cost of release paper, which is unnecessary after transfer, increases. Furthermore, if the period between manufacturing the release paper and applying the elastomer solution such as urethane is prolonged, the release layer may deteriorate due to oxidation or bleeding of additives, resulting in changes in peeling force or severe deterioration. In some cases, when applying an elastomer solution such as urethane, there has been a problem in that repellency occurs. In addition, with silicon-coated release paper, when the release paper is rolled up, the outer surface of the release paper base and the silicone layer are in close contact, so some of the silicon is transferred to the outer surface of the release paper base, and then the urethane When an elastomer solution such as is applied and rolled up, the silicon transferred to the outer surface of the release paper base material is similarly transferred to the elastomer layer, resulting in poor adhesion of printing ink during post-processing.
This sometimes caused poor adhesion when bonded to other base materials. On the other hand, the lining method using a coextruded film of polyolefin resin and thermoplastic elastomer resin proposed in Japanese Patent Application No. 56-099418 forms a release layer and an elastomer layer at the same time, which is a disadvantage of the conventional transfer method. has been resolved. However, in order to increase added value and develop a wider range of applications, it is difficult to print on the elastomer layer or vapor-deposit metals such as aluminum with a coextruded film of polyolefin resin and thermoplastic elastomer resin. In other words, film elongation occurs due to the tension applied on the printing machine during printing, the heat when printing ink dries, the tension during vapor deposition processing, and the heat during drying of the anchor coating agent for vapor deposition, which causes the printing registration to change. It is not practical if defects or cracks in the deposited film occur and post-processing is required. The present invention solves the above-mentioned drawbacks, and uses a coextrusion method to simultaneously manufacture a release sheet and form a thermoplastic elastomer layer in one step, and also to improve suitability for post-processing such as printing and metal vapor deposition. This invention relates to a method for producing an excellent laminate. That is, it is characterized by co-extrusion coating a thermoplastic elastomer and a polyolefin resin to serve as a release layer on a dimensionally stable base sheet such as paper or biaxially stretched plastic film so that the polyolefin resin is on the base material side. This is a method for manufacturing a laminate. Here, the paper or biaxially oriented plastic film used as the base sheet is one that is generally used for release paper and can be used as is, but from the viewpoint of cost and dimensional stability, kraft paper or biaxially oriented polypropylene film, biaxially oriented Stretched polyester film is most suitable. In addition, the polyolefin resin that becomes the release layer is
It is a resin with excellent extrusion processability that has peelability with thermoplastic elastomers and can be used as a support for thermoplastic elastomers that do not have very good processability during coextrusion processing.For example, low density polyethylene, medium density polyethylene, high Density polyethylene, polypropylene, polymethylpentene, polybutene, and polyolefins that are copolymer resins of these can be used, but polyethylene, which is cheaper in cost,
Polypropylene is suitable. Here, in order to adjust the peeling force between the polyolefin resin layer and the thermoplastic elastomer layer, which will be the peeling layer,
Adding modified polyolefin resin to polyolefin resin was very effective. If the adhesive strength between the polyolefin resin layer and the thermoplastic elastomer layer is weak, the thermoplastic elastomer layer will lift during printing or when applying adhesive when laminating with other substrates, resulting in poor printing or problems at the time of lamination. It causes wrinkles. Modified polyolefin resin is a copolymer resin of ethylene and an unsaturated carboxylic acid or a derivative thereof, or a copolymer resin of ethylene, vinyl acetate, and an unsaturated carboxylic acid or a derivative thereof, and specifically, polyethylene or ethylene vinyl acetate. A copolymer resin is graft-polymerized with a carboxylic acid group, an acid anhydride group, and a derivative thereof. These carboxylic acids, acid anhydrides, and derivatives thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, methacrylic anhydride, maleic anhydride, methyl methacrylate, ethyl methacrylate, glycidyl acrylate, and glycidyl methacrylate. etc. As a result of various studies regarding lifting during printing and adhesive coating, we have empirically found that the peeling force between the polyolefin resin layer and the thermoplastic elastomer layer is 5 to 10 g/5 cm.
Below (Tensilon tensile tester, peeling speed 300mm/
min), floating tends to occur, but in order to improve this, modified polyolefin is added at 5 to 50 wt%.
By adding it, the peeling force can be increased from 10g/5cm to 150
g/5cm, and the floating was eliminated. Next, thermoplastic elastomer is a thermoplastic resin that has rubber elasticity, and the representative ones are 2
A thermoplastic urethane elastomer made by reacting a functional polyol, glycol, and diisocyanate at an NCO/OH ratio of 0.95 to 1.1, and a polyester elastomer made of a block copolymer of a crystalline hard segment polyester and an amorphous polyester. , polyvinyl chloride modified by copolymerization with a plasticizer or comonomer, 1-2 polybutadiene, styrene-butadiene block copolymer, styrene-α-olefin block copolymer, or polyisobutylene. Next, the manufacturing method of the present invention will be specifically described with reference to the drawings. As shown in FIG. 1, a polyolefin resin 2 and a thermoplastic elastomer 3 are formed into a hot melt film by a coextrusion device 4 on a paper or biaxially stretched plastic film base sheet 1.
is coated so that it is on the base sheet 1 side. Here, in order to increase the adhesive strength between the base sheet and the polyolefin resin layer, the base sheet is heated or surface treated by corona discharge, and furthermore, an anchor coating agent is applied, etc., as appropriate. In FIG. 1, numeral 5 indicates this surface treatment device. Although the thickness of the polyolefin resin layer is not particularly limited, it is suitably 15 to 30 microns in consideration of the adhesive strength with the base sheet. Further, the thickness of the thermoplastic elastomer is determined depending on the intended use, but a thickness of 2μ to 50μ is suitable for taking advantage of the features of the present invention. The features of the present invention described above are summarized as follows. (1) Since the release sheet and the thermoplastic elastomer layer are manufactured simultaneously in one process using the coextrusion method, it is possible to significantly reduce costs compared to conventional methods. (2) Since paper or biaxially stretched plastic film is used as the base sheet, it has excellent dimensional stability.
Excellent suitability for post-processing to increase added value such as printing and metal vapor deposition. (3) The peeling force can be adjusted by adding a modified polyolefin that has adhesive properties to a thermoplastic elastomer to the polyolefin resin layer that is the peeling layer. (4) Since the release layer and the thermoplastic elastomer layer are formed simultaneously, there is no deterioration such as oxidation or other deterioration over time of the surface of the release layer that occurs in conventional methods, and the release force is stable. Examples of the present invention will be described below. <Example 1> Using the coextrusion apparatus shown in Fig. 1, thermoplastic urethane elastomer (Pandex T-5180, manufactured by Nippon Reichhold) and polypropylene (Noblen FL25F, manufactured by Mitsubishi Yuka) were heated at a resin temperature of 200°C. Under the condition of 220℃, the resin thickness is
Melt extrusion coating was carried out on biaxially oriented polypropylene substrates that had been subjected to corona discharge surface treatment to have a thickness of 15μ and 25μ, to obtain a good laminate in which each layer had a uniform thickness. The peeling force between the polypropylene layer and thermoplastic urethane elastomer layer is 23g/5cm.
Width (Tensilon tensile test, peeling speed 300mm/min)
It was hot. <Example 2> Using the coextrusion apparatus shown in Figure 1, a thermoplastic urethane elastomer (Elastlan E185PMoo manufactured by Nippon Elastran) and the following three types of polyolefin resins were heated at resin temperatures of 180°C and 220°C, respectively. Three types of laminates were obtained by melt extrusion coating on kraft paper coated with a urethane anchor coating agent so that the resin thickness was 10μ and 20μ, respectively. (Polyolefin resin formulation) Polyethylene Polyethylene/modified polyolefin = 90/10 Polyethylene/modified polyolefin = 70/30 [Polyethylene Mirason 14: Modified polyolefin manufactured by Mitsui Polychemicals Modic E300 K: Made by Mitsubishi Yuka, anhydrous ethylene vinyl acetate copolymer resin Modified maleic acid. ] The table below shows the results of evaluating the peel strength of three types of laminates, suitability for printing with urethane gravure ink, and suitability for lamination with stretchable polyester knit.
Shown in 1.

[Table] From the results in Table 1, it is clear that the addition of modified polyolefin has the effect of adjusting the peeling force, and can be adapted to meet the physical properties required in post-processing such as printing, metal deposition, lamination, etc.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a coextrusion laminating apparatus used in an example of the present invention. 1... Release paper base material winder, 2... Polyolefin resin extruder, 3... Thermoplastic elastomer extruder, 4... Coextrusion device, 5... Surface treatment device.

Claims (1)

[Scope of Claims] 1. A thermoplastic elastomer and a polyolefin resin serving as a release layer are coextruded and coated on a base sheet with good dimensional stability so that the polyolefin resin is on the base sheet side. A method for producing a laminate of a release sheet and a thermoplastic elastomer. 2. The manufacturing method according to claim 1, wherein the base sheet is paper or a biaxially stretched plastic film. 3. The manufacturing method according to claim 1 or 2, wherein the polyolefin resin is polyethylene or polypropylene. 4. The manufacturing method according to claim 1 or 2, wherein the polyolefin resin is a mixture of polyethylene or polypropylene and a modified polyolefin resin.