JP2000153589A - Laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate excellent in thermal laminating processability and also excellent in adhesion processability by a high frequency welder, heat resistance and flexibility. SOLUTION: In a laminate having an inner layer containing a polyethylene resin with an m.p. of 100-120 deg.C, an intermediate layer containing an ethylene/ vinyl acetate copolymer with a vinyl acetate content of 15-30 wt.% and an outer layer containing a polyethylene resin with an m.p. of 120-130 deg.C, a ratio of the thickness of the intermediate layer and the sum total thickness of the inner and outer layers is intermediate layer/(inner layer + outer layer) = 2/1-6/1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated body for tarpaulin used as a base material for a partition or the like. More specifically, the present invention relates to a laminate which is excellent in thermal lamination processability between laminates sandwiching a fiber base material in production of a tarpaulin by thermal lamination, and excellent in adhesive processability and flexibility by a high frequency welder. .

[0002]

2. Description of the Related Art Conventionally, a sheet in which a fibrous base material is covered with a synthetic resin film, so-called tarpaulin, has been used for a flexible container, a waterproof sheet, a partition sheet, a bag, a bag, and the like. As a synthetic resin film used for the terpoly, a soft polyvinyl chloride resin film is widely used in terms of flexibility, workability, texture, etc. Recently, however, environmental problems and soft polyvinyl chloride resin film have been used. Due to problems such as bleeding out of the plasticizer incorporated in the resin film, use of a polyolefin resin film such as a polyethylene resin film or a polypropylene resin film instead of the soft polyvinyl chloride resin film is expected. However, the polyolefin-based resin is non-polar, so that a tarpaulin made of a polyolefin-based resin film has a problem in that it is difficult to perform the bonding process using a high-frequency welder and the processability is poor.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a tarpaulin by thermal laminating, which is excellent in heat laminating processability between laminates sandwiching a fiber base material, and excellent in high-frequency welder adhesion and flexibility. It is an object of the present invention to provide a tarpaulin laminate.

[0004]

The gist of the present invention is as follows.
An inner layer containing a polyethylene resin having a melting point of 100 to 120 ° C., (2) an intermediate layer containing an ethylene-vinyl acetate copolymer having a vinyl acetate content of 15 to 30% by weight, and (3) a melting point of 120. A laminate having an outer layer containing a polyethylene-based resin at a temperature of up to 130 ° C., wherein the ratio of the thickness of the intermediate layer to the total thickness of the inner layer and the outer layer is: intermediate layer / (inner layer + outer layer) = 2 / 1 to 6/1.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The polyethylene resin used for the inner layer of the laminate of the present invention is a polyethylene resin having a melting point represented by a peak temperature in differential scanning calorimetry (DSC) of 100 to 120 ° C. If the melting point is less than 100 ° C., there is a problem in terms of shape stability of the laminate, such as warpage. Melting point is 12
When the temperature exceeds 0 ° C., the heat lamination processability between the laminates may be reduced. The polyethylene-based resin having a melt index (MI) of 1.0 to 5.0 g / 10 minutes is preferable because of good moldability when producing a laminate. As the polyethylene resin, a homopolymer of ethylene, a copolymer of ethylene and a monomer copolymerizable with ethylene such as α-olefin, and a mixture thereof can be used. Among them, high-pressure low-density polyethylene (HP
LD) is preferred from the viewpoint of heat lamination processability. As the α-olefin, propylene, butene-1, pentene-
1, hexene-1, octene-1, 4-methylpentene-1 and the like. The proportion of ethylene in the polyethylene resin is preferably at least 80% by weight.

The ethylene-vinyl acetate copolymer used in the intermediate layer of the laminate has a vinyl acetate content of 15 to 30% by weight. When the content of vinyl acetate is less than 15% by weight, the high frequency welder adhesion of the tarpaulin produced using the laminate of the present invention is inferior, and when it exceeds 30% by weight, the laminate is difficult to mold and the appearance is inferior. The content of vinyl acetate is preferably from 18 to 25% by weight, particularly preferably 20 to 25% by weight.
Preferably it is 25% by weight. Further, the ethylene-vinyl acetate copolymer has a melt index of 1.0 to 5.
0 g / 10 min is preferable because of good moldability.

The polyethylene resin used for the outer layer of the laminate is a polyethylene resin having a melting point of 120 to 130 ° C. represented by a peak temperature in differential scanning calorimetry (DSC). When the melting point is lower than 120 ° C., the heat resistance of the tarpaulin may be insufficient, and the heat lamination processability between the laminates may be reduced. 13 melting point
If the temperature exceeds 0 ° C., the high-frequency welder adhesion of the tarpaulin may be insufficient. The polyethylene resin,
Melt index (MI) is 1.0 to 5.0 g / 10
It is preferable that the content is sufficient because the moldability in producing the laminate is good. As the polyethylene resin, a homopolymer of ethylene, a copolymer of ethylene and a monomer copolymerizable with ethylene such as α-olefin, and a mixture thereof can be used. Among them, linear low-density polyethylene (LLDPE) is preferable in terms of transparency. Examples of the α-olefin include propylene, butene-1, pentene-1, hexene-1, octene-1, and 4-methylpentene-1. The proportion of ethylene in the polyethylene resin is preferably at least 80% by weight.

[0008] Each layer of the laminate may be blended with another thermoplastic resin within a range not to impair the object of the present invention. Further, each layer may contain an antioxidant, an inorganic filler (anti-blocking agent), an ultraviolet absorber, a light stabilizer, an antistatic agent, a flame retardant, a colorant (pigment, dye), an inorganic filler, etc., as necessary. Various additives can be blended. Examples of the antioxidant include phenols such as 2,6-di-t-butyl-4-methylphenol and 2,4-dimethyl-6-t-butylphenol, amines such as phenyl-α-naphthylamine and diphenylamine, and phosphines. Phyto-based antioxidants are exemplified.

Examples of the inorganic filler include silica and zeolite. Examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, salicylic acid-based, and phthalic acid-based ultraviolet absorbers. Examples of the light stabilizer include a hindered amine light stabilizer. Examples of the antistatic agent include cationic antistatic agents such as primary amine salts, tertiary amine salts, and pyridine derivatives, metal salts of higher fatty acids, alkylphenol sulfonates, fatty acid ethyl sulfonates, and alkyl sulfonates. And anionic antistatic agents such as phosphoric acid ester salts, nonionic antistatic agents such as polyethylene glycol, and amphoteric antistatic agents such as carboxylic acid derivatives.

[0010] Examples of the flame retardant include antimony oxide. Examples of the coloring agent include carbon black, phthalocyanine, quinacridone, azo pigments, titanium oxide, and red iron oxide. Examples of the inorganic filler include glass fiber, asbestos, mica, aluminum silicate, calcium carbonate, and the like.

The ratio of the thickness of each layer of the laminate is intermediate layer / (inner layer + outer layer) = 2/1 to 6/1. The thickness ratio is 2/1
If it is less than 1, the high frequency welder adhesion of the tarpaulin will be poor, and if it exceeds 6/1, the processability will be poor. The ratio of the thickness of each layer is preferably intermediate layer / (inner layer + outer layer) = 2/1 to 4/1. Furthermore, the inner layer / outer layer is preferably 1/2 to 2/1, and more preferably the inner layer / outer layer is 1/1. Most preferably, inner layer / intermediate layer / outer layer = 1/4/1 to 1/8/1.

The thickness of the laminate is not particularly limited, but is usually 0.05 to 0.5 mm. The outer layer of the laminate may be printed. In that case, the surface is preferably subjected to corona treatment. The laminate can be manufactured using, for example, a known multilayer coextrusion molding machine or a multilayer inflation molding machine. Using two obtained laminates, a fibrous base material is inserted between the inner layer surfaces of the laminate, and a heat lamination process is performed to obtain a tarpaulin. By bonding this tarpaulin to a high frequency welder at an oscillation frequency of 40 to 70 MHz, a partition, a mini house, a bag, and the like are manufactured.

[0013]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. <Evaluation test method> (1) Heat laminating processability A polyester plain woven fabric (400 denier, density (T8, W4)) was inserted between the inner layers of the two laminates, and a table laminator (Tester Sangyo Co., Ltd. )) To evaluate the thermal laminating processability: ○: Adhesive, non-peelable of two laminates △: Adhesive, but sticks to or adheres to laminate roll ×: Adhesive Not possible, the two laminates are peeled off. When the temperature of the laminating roll is 115 ° C. (laminating speed; 1 m / min, pressure: 3.5 kg / cm ² ), the temperature is insufficient and both the examples and comparative examples adhere. It was impossible.

(2) Adhesion of high frequency welder Two pieces of tarpaulin (sample (1) evaluated as “O” or “△” in the heat laminating process) were laminated, and a high frequency welder (oscillation frequency 45 MHz, output 3. 5k
w, oscillation time 4 seconds), and the high frequency welder adhesion is evaluated. ：: Adhered, peeling between tarpaulins not possible ×: Adhesive not possible, peeling at interface between tarpaulins

(3) Heat Resistance Tarpaulin (the sample (1) evaluated as “「 or Δ ”in the heat laminating processability) was placed in a 110 ° C. oven for 3 hours, and the appearance change was visually observed. ：: no deformation △: warpage and curl are observed ×: warpage and curl are large, and the whole is wavy

<Preparation of Laminate> Examples 1 to 3 and Comparative Examples 1 to 3 Using the resins shown in Table 1, a three-layer co-extrusion molding machine manufactured by Plastic Engineering Laboratory was used to form a laminate having a thickness of 0.08 mm. Inner layer /
A laminate comprising an intermediate layer / outer layer was obtained. Each laminate was evaluated. The results are shown in Table 1.

[0017]

[Table 1]

Explanation of symbols in the table PE-1: UF441 (LLDPE) manufactured by Nippon Polychem Co., Ltd., density: 0.924 g / cm ³ , MI: 1.9 g / 10 minutes PE-2: 〃 SF840 (LLDPE), density 0.929 g / cm ³ , MI; 2.6 g / 10 min PE-3: 〃 LC500 (HPLD), density; 0.918 g / cm ³ , MI; 4.0 g / 10 min PE-4: 〃 LF440HB (HPLD), density 0.95 g / cm ³ , MI; 2.8 g / 10 min PE-5: 〃 HY540 (HDPE), density; 0.960 g / cm ³ , MI; 1.0 g / 10 min EVA-1: LV540 manufactured by Nippon Polychem Co., Ltd. , MI; 2.5 g / 10 min EVA-2: EV460, manufactured by Mitsui Dupont Co., Ltd .; MI; 2.5 g / 10 min EVA-3: LV360, manufactured by Mitsui Dupont, MI; 2.0 g / 10 min EVA- 4: Nippon Polychem Corp. LV350, MI; 3.5 g / 10 min EVA-5: Mitsui DuPont Corp. EV40LX, MI; 2.0 g / 10 min

Thermal laminating conditions (1): Laminating roll temperature; 120 ° C., laminating speed: 1 m / min, pressure: 3.5 kg / cm ² (2): Laminating roll temperature: 125 ° C., laminating speed: 1 m / min , Pressure; 3.5kg / cm ²

[0020]

The laminate of the present invention is excellent in heat laminating property at the time of producing tarpaulin, and excellent in adhesiveness and heat resistance by a high frequency welder.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshiaki Fukui 2nd Oike, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi F-term (reference) 4F100 AK04A AK04C AK06C AK63A AK68B BA03 BA06 BA10A BA10C BA16 BA25 BA26 EH202 GB08 JA04A JA04C JJ03 JL01 JL12 YY00A YY00C

Claims (3)

[Claims] 1. An intermediate layer containing (1) an inner layer containing a polyethylene resin having a melting point of 100 to 120 ° C., and (2) an ethylene-vinyl acetate copolymer having a vinyl acetate content of 15 to 30% by weight. Layer, (3) melting point of 120 to 130
A laminate having an outer layer containing a polyethylene resin at a temperature of 0 ° C., wherein the ratio of the thickness of the intermediate layer to the total thickness of the inner layer and the outer layer is: intermediate layer / (inner layer + outer layer) = 2/1 to 1
A laminate, wherein the ratio is 6/1. 2. The laminate according to claim 1, wherein the polyethylene resin of the outer layer is a linear low-density polyethylene. 3. The laminate according to claim 1, wherein the polyethylene resin of the inner layer is a high-pressure low-density polyethylene.