JPH10166522A - Flexible laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laminate excellent in emboss retention, writing mark restoring properties and resistance to ink transfer by a constitution wherein the flexible laminate has two layers or an outermost layer made of polyolefin- based resin material, the sebum swelling of which is a specified value or less and a layer made of polyolefin based resin material, the D type durometer hardness of which is a specified value or less. SOLUTION: This flexible laminate has at least two layers or an outermost layer made of polyolefin-based resin material A, the sebum swelling of which is 10wt.% or less and a layer made of polyolefin-based resin material B, the D type durometer hardness of which is 45 or less. As the outermost polyolefin- based resin material A, a copolymer of ethylene having the ethylene content of 90-98wt.% and a polar group-containing monomer is employed. When the ethylene content is 90wt.% or less, inferior sebum swelling properties result. When the ethylene content exceeds 98wt.%, inferior emboss retention and writing mark restoring properties result. The combination of the fundamental constitution of this flexible laminate is fundamentally A/B and A/B/A. As the laminating method of the laminate, a coextrusion molding method with a T-die or an inflation molding method is employed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin flexible sheet having a low degree of sebum swelling and excellent in surface retention, writing trace recovery, ink transfer resistance and the like. More specifically, the present invention relates to a desk mat, table cloth, and the like. The present invention relates to a flexible laminate in which the shape of a flexible sheet material used in places touched by human hands, such as a keyboard cover and a switch cover, due to sebum swelling is reduced over time.

[0002]

2. Description of the Related Art Conventionally, desk mats, table cloths,
In the field of flexible sheets such as keyboard covers, soft vinyl chloride resin is used, and at present, most of the market is dominated by soft vinyl chloride resin (hereinafter referred to as PVC). However, this application has a relatively short product life cycle,
It is becoming a major problem in global environmental protection in terms of sending a large amount of PVC waste to the world. To cope with these problems, each PVC maker has been studying alternative materials using polyolefin resin materials, but at present, a material that is at least equivalent to soft PVC in terms of price, processability, and performance is determined. The version is undeveloped. Among them, in the field of sheets such as desk mats, which are relatively easy to replace, ethylene-based binary copolymers have been studied from a relatively early stage, and some of them are currently in practical use.

[0003]

However, since this application is used in a state where bare hands are in constant contact, deformation of the shape caused by migration and swelling of cosmetics such as sebum or hand cream used in hands is ignored. As a problem that cannot be done, the replacement of PVC in this application is being braked. Further, a method of applying a sebum-barrier coating such as an ultraviolet-curable film on these surfaces has also been proposed, but has a problem in uniformity and economical efficiency of the coating film. The present invention solves the above-mentioned problems of the prior art, is economically excellent,
An object of the present invention is to provide a flexible laminate which does not have sebum swelling deformation and is excellent in texture retention, handwriting recovery, ink transfer resistance, and the like.

[0004]

The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, by combining a material having a specific degree of sebum swelling with a flexible sheet having a specific hardness. The present inventors have found that a flexible laminate having a low degree of sebum swelling and maintaining good embossing property and recovery of writing marks has been obtained, and the present invention has been accomplished. That is, the flexible laminate of the present invention comprises, as an outermost layer, a layer composed of a polyolefin resin material A having a sebum swelling degree of 10% by weight or less and a layer composed of a polyolefin resin material B having a D-type durometer hardness of 45 or less. It has at least two layers. In this case, a three-layer structure in which a layer made of the resin material B is used as an intermediate layer, and a layer made of the resin material A is provided on both outer layers. The resin material A has an ethylene content of 90% by weight to 98% by weight.
Copolymer of ethylene and a polar group-containing monomer (A)
1) or non-polar low density polyethylene (A2),
Alternatively, 10 to 45% by weight of a copolymer of ethylene and a polar group-containing monomer (A1), a polyolefin resin (A0) and / or a nonpolar low-density polyethylene (A2)
A resin composition (A3) with 90 to 55% by weight is preferred.
Examples of the copolymer (A1) of ethylene and a polar group-containing monomer include a copolymer (A1a) of ethylene and an α · β-unsaturated carboxylic acid or a derivative thereof, and / or an ethylene-vinyl ester copolymer (A1b). Is more preferred. Further, a copolymer (A1a) of ethylene and an α · β-unsaturated carboxylic acid or a derivative thereof is ethylene- (meth)
Copolymer with acrylic acid or its derivative (A11a)
And an ethylene-vinyl ester copolymer (A1b)
Is preferably an ethylene-vinyl acetate copolymer (A11b). The non-polar low-density polyethylene (A2) includes a low-density polyethylene (A21) obtained by high-pressure radical polymerization and / or a density of 0.86 to 0.94 g.
/ Cm ³ ethylene-α-olefin copolymer (A22)
It is preferred that Further, in the resin composition (A3), a copolymer (A1) of ethylene and a polar group-containing monomer is a copolymer (A1a) of ethylene and an α · β-unsaturated carboxylic acid or a derivative thereof, and Or an ethylene-vinyl ester copolymer (A1b), wherein the nonpolar low-density polyethylene (A2) is a low-density polyethylene (A21) obtained by high-pressure radical polymerization, and / or a density of 0.1.
It is preferably an ethylene-α-olefin copolymer (A22) of 86 to 0.94 g / cm ³ . In addition, resin material B
Is preferably a copolymer (B1) of ethylene and a polar group-containing monomer.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The resin material A used in the present invention is composed of a polyolefin resin material having a sebum swelling degree of 10% by weight or less. The sebum swelling degree of the present invention is 150 × 100 × 3 cut out from a 3 mm press sheet.
mm test piece is immersed in a stearic acid-saturated oleic acid solution at 40 ° C. and shows the rate of weight increase after one week. In the present invention, the degree of sebum swelling is evaluated to substitute for the sebum swelling deformability. Characteristics. If this value does not exceed 10% by weight, preferably 8% by weight, more preferably 7% by weight, there is no problem of temporal deformation of the shape in actual use.

The polyolefin resin (A0) used as the resin material A is not particularly limited as long as it is a polyolefin material having a sebum swelling degree of 10% by weight or less. Examples include polyethylene resins such as high-density polyethylene, polypropylene resins such as propylene homopolymer, and random block copolymers with propylene-α-olefin, and preferably ethylene having an ethylene content of 90% by weight to 98% by weight. (A1), a nonpolar low-density polyethylene (A2), a copolymer of ethylene and a polar group-containing monomer (A1) in an amount of 10 to 45% by weight, and a polyolefin resin (A0). ), Non-polar low density polyethylene (A
Desirable is a resin composition (A3) containing at least one of 90 to 55% by weight of 2).

The copolymer of ethylene having a content of ethylene of 90 to 98% by weight and a monomer having a polar group (A)
Examples of 1) include a copolymer (A1a) of ethylene and an α · β-unsaturated carboxylic acid or a derivative thereof, and an ethylene-vinyl ester copolymer (A1b).

As the copolymer (A1a) of ethylene and α.β-unsaturated carboxylic acid or a derivative thereof, ethylene- (meth) acrylate copolymer (A11)
a), an ethylene- (meth) acrylic acid copolymer (A12
a), an ethylene-maleic anhydride copolymer (A13
a), an ethylene- (meth) acrylate-maleic anhydride copolymer (A14a) and the like. Specific examples include ethylene-methyl acrylate copolymer,
Ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-glycidyl methacrylate, ethylene-vinyl acetate-glycidyl methacrylate, ethylene-methyl acrylate-maleic anhydride copolymer, ethylene-ethyl acrylate-anhydride Maleic acid copolymer, ethylene-methyl methacrylate-maleic anhydride copolymer and the like can be mentioned. Derivatives with these metal salts, amide compounds and the like are also included.

The ethylene-vinyl ester copolymer (A1
b) is a copolymer of ethylene with vinyl formate, vinyl propionate, vinyl acetate, and the like, preferably an ethylene-vinyl acetate copolymer.

The ethylene content of these copolymers is desirably in the range of 90% by weight to 98% by weight, and when the content is 90% by weight or less, the sebum swelling resistance is poor and 98% by weight. If it exceeds the range of%, there is a possibility that the ink may be inferior in the grain retention property and the handwriting recovery property.

The nonpolar low-density polyethylene (A) of the present invention
2) includes low-density polyethylene (A21) obtained by high-pressure radical polymerization, ethylene-α-olefin copolymer (A22) having a density of 0.86 to 0.94 g / cm ³ , and the like.
More specifically, low-density polyethylene obtained by high-pressure radical polymerization, linear low-density polyethylene obtained by ionic polymerization of a Ziegler-based catalyst, a Phillips-based catalyst, a metallocene-based catalyst, and the like, and ultra-low-density polyethylene are exemplified.

As a preferred embodiment of the resin material A of the present invention, 55 to 90% by weight of a copolymer (A1) of ethylene and a polar group-containing monomer, a polyolefin resin (A0), A resin composition (A3) with 10 to 45% by weight of at least one kind of high density polyethylene (A2) is included. More specifically, low-density polyethylene, ultra-low-density polyethylene, low-density polyethylene and ethylene-
A blend with a polar group-containing monomer copolymer (A1),
A blend of an ultra-low density polyethylene and an ethylene-polar group-containing monomer copolymer (A1), a linear low-density polyethylene and an ethylene-functional group-containing monomer copolymer (A
Blend with 1), polypropylene (lantern, block)
And a blend of ethylene-functional group-containing monomer copolymer (A1).

If the copolymer (A1) of ethylene and the polar group-containing monomer is less than 55% by weight, there is no improvement in sebum swelling and deformability.
It does not reach the practical level in the recovery of handwriting.

The polyolefin resin having a D-type durometer hardness of 45 or less of the resin material B of the present invention is not particularly limited as long as the above conditions are satisfied, and may be appropriately selected from the resin materials A. Good. The copolymer (B1) of the ethylene and the polar group-containing monomer is preferable, the copolymer (B1a) of ethylene and an α · β-unsaturated carboxylic acid or a derivative thereof, and the ethylene-vinyl ester copolymer (B1b) Is more preferred. Further, a copolymer with ethylene- (meth) acrylic acid or a derivative thereof (B
11a), ethylene-vinyl acetate copolymer (B11b)
It is desirable that Further, a copolymer of ethylene and a polar group-containing monomer (B1), a polyolefin resin (B0) and / or a non-polar low-density polyethylene (B2)
And the resin composition (B3).

The reason why the hardness is limited is as follows.
If the hardness is higher than this, not only the sheet cannot be said to be a flexible sheet, but also the grain retention property and the handwriting recovery property become problems.

The combination of the basic constitutions of the flexible laminate of the present invention is based on A / B and A / B / A, and A / B / A /
B, a plurality of combinations such as A / B / A / B / A may be used.
Specifically, two layers of (AorA1 or A2 or A3) / (BorB1) or (AorA1 or A2 or A3) / (BorB1)
1) Two or three layers of (AorA1orA2 orA3) are possible. Specific examples of the above include LD / EMA, VL / E
MA, VL / EMMA, LD + EMA / EMA, VL +
EMA / EMA, LD / EMA / LD, VL / EMA /
VL, LD + EMA / EMA / LD + EMA, VL + E
MA / EMA / VL + EMA and the like. (However, LD: low density polyethylene, VL: very low density polyethylene, EMA: ethylene-methyl acrylate, EM
MA: shows ethylene-methyl methacrylate. )

The flexible sheet may be used by laminating or pasting it on another third substrate. Examples of the third base material include paper, metal, non-woven fabric, cloth, rubber, other polyolefin films, resin films other than polyolefin, coated products of the above base materials, surface coated products, surface printed products, or a combination thereof. Examples include multilayer laminates.

If necessary, various conventional additives such as an antiblocking agent, a slip agent, a lubricant, a stabilizer, an antistatic agent and a coloring agent are added to the resin composition constituting the flexible laminate of the present invention. be able to. Examples of the method for preparing the resin material include a dry blending method, an extruder kneading method, and a Banbury mixer method. Lamination method
The conditions and the like are not particularly limited, but T-die by co-extrusion molding or inflation molding is preferable.

[0019]

The present invention will be described more specifically with reference to examples and comparative examples. The upper and lower layers of the resin as shown in Table 1 were molded using a 40 mmφ, 100 mm multilayer T-die sheet molding machine at a resin temperature of 160 ° C., a die width of 900 mm, and a take-up speed of 2 m / mi.
In n, two types of two-layer coextrusion molding were performed, and nip was performed with a mat roll having a surface roughness of 33 μm (cooling water temperature: 20 ° C.) to form a sheet having a thickness of 2 mm without an air knife. The thickness configuration was adjusted so that upper layer / lower layer = 9/1.

The sebum swelling ability was determined by immersing a 150 × 100 × 3 mm test piece cut from a 3 mm press sheet of the upper layer material in a stearic acid-saturated oleic acid solution at 40 ° C., and increasing the weight increase after one week. Was evaluated as a substitute property of the fat swelling deformation. When the weight increase rate was less than 5 wt%, it was evaluated as ○, when 5 to 7 wt%, it was evaluated as Δ, and when it was more than 7 wt%, as ×.

The grain-keeping property was evaluated by the glossiness (gross meter JISK7105) of the upper surface of the formed sheet, and was evaluated as ○ for 10 or less, Δ for 10 to 17 and × for greater than 17.

The handwriting recovery property is as follows.
/ M2 ^high- quality paper, write strongly with a ballpoint pen, remove the paper immediately, visually observe the dents on the surface due to the reflection of the indoor fluorescent lamp,
Those with some dents were marked with △, and those with considerable dents that were difficult to write continuously in the same place were marked with x. The results are shown in Table 1.

[0023]

[Table 1]

EMA1: ethylene-methyl acrylate copolymer (MFR = 2.5, MA content = 15 wt%, D-type durometer hardness = 35) EMA2: ethylene-methyl acrylate copolymer (M
FR = 2.5, MA content = 7 wt%) LDPE: Low density polyethylene by high pressure radical polymerization (d = 0.926 g / cm ³ , MFR = 2.0) RPP: Random polypropylene (MFR = 2.5, ethylene content = LLD: Linear low density polyethylene (d = 0.927 g / c)
^{m 3, MFR = 3.5) HDPE} : high-density polyethylene ^{(d = 0.950g / cm 3,} M
FR2.5) EVA: Ethylene-vinyl acetate copolymer (MFR = 3.
0, VA content = 12%) BPP: Block polypropylene (MFR = 3.0, ethylene content = 7%)

[0025]

The flexible laminate of the present invention is a laminate having a specific sebum swelling polyolefin resin and a specific D-type durometer hardness to provide a sebum swelling property, a carbo-keeping property, a writing trace recovery property, It has excellent ink transfer resistance and is useful as a substitute material for soft PVC.

Claims (10)

[Claims] 1. An outermost layer comprising a polyolefin resin material A having a degree of sebum swelling of 10% by weight or less;
A flexible laminate comprising at least two layers of a polyolefin resin material B having a mold durometer hardness of 45 or less. 2. The method according to claim 1, wherein a layer made of the resin material B is used as an intermediate layer, and a layer made of the resin material A is provided on both outer layers.
The flexible laminate according to claim 1, wherein the flexible laminate has a layered structure. 3. The resin material A has an ethylene content of 90.
The flexible laminate according to claim 1 or 2, which is a copolymer (A1) of ethylene and a polar group-containing monomer in an amount of from 98% by weight to 98% by weight. 4. The flexible laminate according to claim 1, wherein the resin material A is a non-polar low-density polyethylene (A2). 5. The resin material A comprises 10 to 45% by weight of a copolymer of ethylene and a polar group-containing monomer (A1),
The flexible laminate according to claim 1 or 2, which is a resin composition (A3) containing 90 to 55% by weight of a polyolefin-based resin (A0) and / or a nonpolar low-density polyethylene (A2). 6. The copolymer (A1) of ethylene and a polar group-containing monomer, wherein the copolymer (A1a) of ethylene and an α · β-unsaturated carboxylic acid or a derivative thereof, and / or an ethylene-vinyl ester The flexible laminate according to claim 3, which is a copolymer (A1b). 7. The copolymer (A1a) of ethylene and an α.β-unsaturated carboxylic acid or a derivative thereof is a copolymer (A11a) of ethylene- (meth) acrylic acid or a derivative thereof, and -Vinyl ester copolymer (A1b) is an ethylene-vinyl acetate copolymer (A1
The flexible laminate according to claim 6, which is 1b). 8. The non-polar low density polyethylene (A)
2) The low-density polyethylene (A21) obtained by high-pressure radical polymerization and / or an ethylene-α-olefin copolymer (A22) having a density of 0.86 to 0.94 g / cm ^3. Or the flexible laminate according to 5. 9. The copolymer (A1) of ethylene and a polar group-containing monomer is a copolymer (A1a) of ethylene and an α · β-unsaturated carboxylic acid or a derivative thereof, and / or an ethylene-vinyl ester Non-polar low-density polyethylene (A2), which is a copolymer (A1b), is a low-density polyethylene (A21) obtained by high-pressure radical polymerization and / or ethylene-α-olefin having a density of 0.86 to 0.94 g / cm ^3. The flexible laminate according to claim 5, which is a polymer (A22). 10. The flexible laminate according to claim 1, wherein the resin material B is a copolymer of ethylene and a polar group-containing monomer (B1).