JP2007144902A - Multilayer resin sheet and vending machine display using the same - Google Patents

Abstract

A multilayer resin sheet and a vending machine display using the same are provided.
A copolyester resin layer having 100 mol parts of terephthalic acid units, 80 to 60 mol parts of ethylene glycol units and 20 to 40 mol parts of spiroglycol units is laminated on both sides of a polyethylene terephthalate resin layer (core layer). (1) One surface is a mirror surface, (2) The other surface is an embossed surface with an average surface roughness Ra value of 0.3-2 μm, and (3) the thickness of the core layer in the total thickness Is a multilayer resin sheet of 20 to 70%. The multilayer resin sheet of the present invention is excellent in continuous printability, has good thermoformability, good adhesion of printing ink, good heat resistance, and good heat workability. It can be suitably used for advertisement display boards and dummy displays.
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Description

The present invention relates to a multilayer resin sheet and a vending machine display using the same.

A multilayer resin sheet, for example, a single-layer sheet of aromatic polycarbonate (hereinafter referred to as PC) or a biaxially stretched sheet of polyethylene terephthalate (hereinafter referred to as stretched PET) is used as a dummy sheet for vending machines or dummy displays (dummy can samples). It is used. The resin sheet is transparent, and printing is often performed on the back surface of the sheet (see Patent Document 1 and Patent Document 2).

When the multilayer resin sheet is used outdoors, it is exposed to direct sunlight. Even indoor use is heated by, for example, a backlight, so heat resistance is required.

Sheets used for these applications are generally mirror-finished on both sides, and surface protection films are often affixed on both sides to prevent scratches in the processing steps. There has been a desire to omit the step of peeling off the protective film before printing after the processing step.

After printing, it takes time to peel off the other surface protective film before thermoforming, and when the molded products are stacked, the molded products are inferior in slipperiness, and the molded products may not be peeled off.

A method of adding inert particles to the sheet surface has been proposed, but there have been problems such as an increase in cost and an increase in manufacturing steps (see Patent Document 4).

In the resin sheet mainly composed of stretched PET, the sheet supply in the continuous printing process may not be stable. In the case of stretched PET, since the wettability of the surface is poor, it is necessary to improve the adhesion of the printing ink and the transparency of the pattern. Sheets mainly composed of stretched PET could be used for dummy cans, but their shape was limited because they were difficult to thermoform. In recent years, the shape of the dummy can has become complicated, and a sheet with good thermal workability has been demanded.

JP 09-270060 A JP 07-219443 A JP 2004-345344 A JP 2004-345098 A

The present invention provides a multilayer resin sheet having excellent continuous printability, good printing finish, and good thermoformability, and a vending machine display using the same.

In the present invention, a copolymerized polyester resin layer having 100 mol parts of terephthalic acid units, 80 to 60 mol parts of ethylene glycol units, and 20 to 40 mol parts of spiroglycol units is laminated on both sides of a polyethylene terephthalate resin layer (core layer). (1) One surface is a mirror surface, (2) The other surface is an embossed surface with an average surface roughness Ra value of 0.3 to 2 μm, and (3) the thickness of the core layer in the total thickness is It is a multilayer resin sheet which is 20 to 70%.

The multilayer resin sheet of the present invention has features such as excellent continuous printability, good thermoformability, good adhesion of printing ink, good heat resistance, and good transparency of printed designs. It can be suitably used for vending machine displays such as backlit advertising display boards and dummy displays in vending machines.

The present invention is characterized by laminating a copolymer polyester resin layer having 100 parts by mole of terephthalic acid units, 80 to 60 parts by mole of ethylene glycol units, and 20 to 40 parts by mole of spiroglycol units on both sides of the polyethylene terephthalate resin layer. And The core layer is a layer mainly composed of polyethylene terephthalate resin (PET resin).

The resin that forms the core layer only needs to have a polyethylene terephthalate resin skeleton. For example, a resin in which a part of the polyethylene terephthalate resin skeleton is substituted with a halogen, an alkyl group, or the like may be used.

The core layer resin may contain a monomer unit derived from a dicarboxylic acid other than terephthalic acid, or a diol monomer unit other than a monomer unit derived from a diol other than hexamethylene glycol. You may do it. The core layer may contain 80 parts by mass or more of monomer units derived from terephthalic acid and hexamethylene glycol in 100 parts by mass of the polyethylene terephthalate resin.

Examples of dicarboxylic acid monomers other than terephthalic acid include isophthalic acid and adipic acid.

Examples of diol monomers other than hexamethylene glycol include propylene glycol and diethylene glycol.

A core layer having an intrinsic viscosity of 0.75 or more can be suitably used because the drawdown during thermoforming is small.

The copolyester resin is obtained by condensation polymerization of a dicarboxylic acid monomer and a glycol monomer by a method such as a direct esterification method or a direct esterification method.

As the dicarboxylic monomer used in the copolyester resin, terephthalic acid is preferably used. Dicarboxylic acid monomers other than terephthalic acid include aliphatic dicarboxylic acids such as adipic acid, oxalic acid, malonic acid, succinic acid, azelaic acid, sebacic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid Aromatic dicarboxylic acid such as cycloaliphatic dicarboxylic acid such as cyclohexanedicarboxylic acid, dimer acid and the like. The terephthalic acid unit is preferably 90 mol% or more of the entire dicarboxylic acid monomer unit in the copolyester resin.

As glycol monomers used in the copolymerized polyester resin, ethylene glycol and spiro glycol are used. In addition to ethylene glycol and spiroglycol, other diol monomers may be used in combination. Diol monomers other than ethylene glycol and spiro glycol include, for example, diethylene glycol, butanediol, neopentyl glycol, propylene glycol, hexamethylene glycol, 1,4-cyclohexanedimethanol, polyalkylene glycol, bisphenol A or bisphenol S diethoxy Compounds and the like. The total of ethylene glycol units and spiroglycol units is preferably 90 mol% or more of the entire diol monomer units.

The ratio of the diol used for the copolymerized polyester resin is 20 to 40 mol parts of spiroglycol and 80 to 60 mol parts of ethylene glycol in 100 mol parts of all glycol monomers. If the spiroglycol content is low, the heat resistance of the resulting multilayer resin sheet may be reduced, and if the spiroglycol content is high, the impact resistance of the multilayer resin sheet may be reduced.

The ratio of the core layer in the multilayer resin sheet to the total thickness of the multilayer resin sheet is 20 to 70%. If the proportion of the core layer is small, the heat resistance is insufficient, and the molded product may be deformed by direct sunlight and heat from the vending machine backlight, and if the proportion of the core layer is large, the cost increases and the thermoformability deteriorates. There is a case.

The surface roughness (Ra) according to JIS B0601 of the multilayer resin sheet is 0.3-2 μm. If it is less than 0.3 μm, the slipperiness of the sheet surface becomes poor, the paper feeding suitability for automatic printing is lowered, and when the molded products are stacked, troubles such as stacking of the molded products may occur. If it exceeds 2 μm, the printed pattern may have poor transparency.

Antistatic agent is kneaded or applied to the copolyester resin layer formed on the mirror surface of the multilayer resin sheet to prevent automatic paper feeding troubles due to static electricity and to prevent dust from adhering to the molded product. It is preferable to use an agent layer.

The antistatic agent is not particularly limited. For example, cationic antistatic agents such as lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, lauryldiethanolamine, stearylamine hydrochloride, alkylphosphate diethanolamine, potassium alkylphosphate, alkylbenzenesulfonates, etc. Anionic antistatic agents, polyoxyethylene tridecyl ether, polyoxyethylene lauryl ether, polyethylene glycol monooleate, polyoxyethylene sorbitan monooleate, and the like.

The thickness of the multilayer resin sheet is preferably 0.2 to 0.7 mm. If the multilayer resin sheet is thin, the sheet is weak and the strength of the molded product may be insufficient. If the multilayer resin sheet is too thick, it is uneconomical.

For multilayer resin sheets, colorants such as pigments and dyes, mold release agents such as silicone oil and alkyl ester, fibrous reinforcing agents such as glass fiber and carbon fiber, granular lubricants such as talc, clay and silica, polyester and Plasticizers such as polycarbonate oligomers, ultraviolet absorbers and the like may be added as appropriate.

The manufacturing method of a multilayer resin sheet is not specifically limited, A general method can be used. As a manufacturing procedure, for example,
(1) Two types of films are produced by extruding a copolymer polyester resin layer for a mirror surface and an embossed surface and a core layer with two single-screw extruders.
(2) After a core layer is sandwiched between a copolymer polyester resin layer for a mirror surface and a copolymer polyester resin layer for an embossed surface, a multi-layer sheet is formed by a feed block and a T die.
(3) A method of embossing the obtained multilayer sheet can be mentioned. A multi-manifold die may be used for the production of the multilayer sheet.

There may be an intermediate layer such as an adhesive layer or a barrier layer between the mirror surface layer and the core layer and between the embossed layer and the core layer.

The method for embossing the multilayer resin sheet is not particularly limited. For example, when the multilayer resin sheet extruded from the die is taken up, the embossed surface is disposed on the embossing roll side, and the metal mirror roll / The method of passing between embossing rolls is mentioned.

Although the usage method of a multilayer resin sheet is not specifically limited, For example, after feeding to a printing apparatus continuously with an automatic machine and performing a predetermined printing, the method of heat-molding etc. are mentioned.

Since the multilayer resin sheet is easy to continuously feed and has good thermoformability, it can be suitably used for vending machine displays such as backlit advertising display boards and dummy displays in vending machines.

(Materials used)
<Monomer for copolymer polyester resin>
Terephthalic acid: reagent grade 1, commercially available.
Ethylene glycol: Reagent grade 1, commercially available.
Spiroglycol: A commercial product manufactured by Nippon Hydrazine Kogyo.

<Core layer>
Polyethylene terephthalate resin: PET resin, commercially available product, intrinsic viscosity 0.82.

<Copolymerized polyester resin layer (mirror surface layer and embossed layer)>
Copolymerized polyester resin: Copolymerized polyester resin obtained by mixing 25 mol parts of ethylene glycol, 25 mol parts of spiroglycol and 50 mol parts of terephthalic acid at a predetermined molar ratio, and polymerized by a direct esterification method, a commercial product.
Antistatic agent: Commercially available mainly composed of quaternary ammonium compounds.

(Resin multilayer sheet)
Using the above resin raw materials, a two-layer three-layer resin multilayer sheet composed of a mirror layer / core layer / emboss layer was obtained by a feed block method using two 40 mm single-screw extruders. The resin multilayer sheet extruded from the T-die was sandwiched between rolls by a mirror-finished cast roll and emboss rolls having different surface states, and taken up. About what has an antistatic agent, it apply | coated to the gloss surface and the multilayer resin sheet of Table 1 or less was obtained.

(Spiroglycol copolymer ratio in the copolymerized polyester resin layer)
The copolymer polyester resin is dissolved in a mixed solution (1: 1) of deuterated trifluoroacetic acid and deuterated chloroform, an internal standard substance is added, and each monomer unit is measured using an FT-NMR apparatus. The content of was quantified. From the content of each monomer unit, the molar ratio of the spiroglycol monomer unit to the whole diol monomer unit in the copolymerized polyester resin layer was measured.
FT-NMR apparatus: 300MG type internal standard substance manufactured by Varian: Tetramethylsilane (TMS)

In Comparative Example 6 and Comparative Example 7, the following sheets were used.
Comparative Example 6: PC single-layer sheet, trade name Panlite, manufactured by Teijin Chemicals Ltd.
Comparative Example 7: Stretched PET sheet, trade name Cosmo Shine, manufactured by Toyobo Co., Ltd.

(Sheet surface roughness Ra)
The average surface roughness (Ra value) of the multilayer resin sheets obtained in Examples and Comparative Examples was measured using a stylus type surface roughness measuring device in accordance with JIS B0601. The evaluation results are shown in Table 1.
Measuring machine: Surfcom 120A manufactured by Tokyo Seimitsu Co., Ltd.

(Copolymerized polyester resin layer thickness ratio)
The layer structure of the multilayer resin sheet obtained in Examples and Comparative Examples was observed with a laser microscope. The ratio of the total thickness of the mirror surface layer and the embossed layer made of the copolyester resin to the total thickness of the multilayer resin sheet was determined. The results are shown in Table 1.
Laser microscope: KEYENCE VK-8500.

(Continuous printability)
Each sheet was subjected to a screen printing automatic machine to evaluate the continuous printability.
The evaluation criteria are as follows. The evaluation results are shown in Table 1.
○: Good slipperiness and smooth sheet supply.
X: Sliding property is poor and sheet supply trouble occurs.

(Transparency of printed design)
For the embossed surface of the multilayer resin sheet and Comparative Examples No. 1-7 and No. 1-8, print the image using screen ink on the surface where the protective film on one side was peeled off, and visually observe it from the non-printed side Went.
○: Transparency of printed pattern is sufficient.
X: The transparency of the printed pattern is insufficient.

(Thermoformability)
The multilayer resin sheet and the sheets obtained in Experiment No. 1-7 and Experiment No. 1-8 were formed into dummy cans by using a vacuum molding machine with a sheet surface temperature of 160 ° C. Shape). ○: There is no problem in formability.
X: Elongation during heating is small and shaping is difficult.

(Heat resistance evaluation)
The dummy can-shaped molded product was left in an oven at 100 ° C. for 6 hours and then evaluated visually.
○: Deformation is not seen.
X: Deformation is seen.
The evaluation results are shown in Tables 1 to 5.

The multilayer resin sheet of the present invention is excellent in continuous printability, has good thermoformability, good adhesion of printing ink, good heat resistance, and good heat workability. It can be suitably used for advertisement display boards and dummy displays.

Claims (5)

On both sides of the polyethylene terephthalate resin layer (core layer), a copolymer polyester resin layer having 100 parts by mole of terephthalic acid units, 80 to 60 parts by mole of ethylene glycol units, and 20 to 40 parts by mole of spiroglycol units is laminated, (1) One surface is a mirror surface, (2) The other surface is an embossed surface having an average surface roughness Ra value of 0.3 to 2 μm, and (3) the thickness of the core layer in the total thickness is 20 to 70 % Multilayer resin sheet. The multilayer resin sheet according to claim 1, wherein the mirror-side surface layer contains an antistatic agent. The multilayer resin sheet according to claim 1, further comprising an antistatic agent layer on a mirror surface. The multilayer resin sheet according to any one of claims 1 to 3, which has a thickness of 0.2 to 0.7 mm. A vending machine display using the multilayer resin sheet according to any one of claims 1 to 4.