JPH09272191A - Multilayered polyester sheet and container consisting of it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent slip properties, scratch resistance, cut properties and adhesive properties by laminating a skin layer of a specified copolyester on one face of a core layer of a specified polyester and making thickness of the whole skin layer and intrinsic viscosity of the whole layer of the sheet respectively to a specified value. SOLUTION: A multilayered sheet is prepd. by laminating a skin layer on one face of a core layer. The skin layer consists of a copolyester wherein terephthalic acid is a main acid component and 10-90mol% ethylene glycol and 90-10mol% 1,4-cyclohexane dimethanol are glycol components and 10-5,000ppm inert particles with a mean particle diameter of 0.5-30μm and 0.1-5wt.% ester compd. with the total carbon number of 30-60 consisting of an aliph. alcohol and an aliph. monocarboxylic acid are incorporated. The core layer consists of a polyester wherein terephthalic acid is a main acid component and ethylene glycol is a main glycol component. In addition, thickness of the whole skin layer is 3-50% of the whole layer and intrinsic viscosity of the whole layer of the sheet is 0.5-1.1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester sheet having improved slipperiness, cuttability and solvent adhesion without impairing transparency.

[0002]

2. Description of the Related Art Saturated polyesters, particularly crystalline polyester resins represented by polyethylene terephthalate (hereinafter abbreviated as PET) are widely used as a polymer for sheets and films as well as for fibers. Utilizing its chemical resistance and low gas permeability, it has come to be applied to carbonated drinks, juice bottles, beverage bottles such as beer, cosmetic containers, food trays, and the like.

Among them, an amorphous polyester sheet called A-PET has attracted attention for its excellent recyclability, low pollution and food safety, and its use amount has rapidly increased in recent years as a packaging material replacing vinyl chloride and polystyrene. ing. This polyester sheet is used as a blister pack for foods and medicines and miscellaneous goods by thermoforming, and is also used as a clear case in which cosmetics and electric devices are put in by making use of its excellent transparency.

Conventionally, when such a polyester sheet is used as a clear case, there are problems such as blocking of the sheets during conveyance on the production line and difficulty of cutting because of poor sliding properties of the sheet. Was wanted.

Many proposals have hitherto been made on a method for improving the slipperiness of a polyester sheet. For example, as a method of precipitating internal particles and a method of adding inert particles, JP-A-53-14753 and JP-A-4-13626 are known.
No. 3, etc. are known, but this method cannot be said to be a satisfactory method because satisfactory slipperiness cannot be obtained unless the addition amount is increased, and transparency is lowered when the addition amount is too large. .

There is also a method of applying silicon to the surface, but with this method it is difficult to perform uniform application and drying, so the physical properties of the product are not stable, and the printability and adhesiveness are also reduced. It is hard to say that this is a satisfying method.

As another method, a high molecular weight chain polyester obtained by copolymerizing a divalent alicyclic alcohol with an aromatic dicarboxylic acid and a divalent aliphatic alcohol is used for the front surface layer and the back surface layer. A sheet is also proposed (Japanese Patent Laid-Open No. 5-1622271). This is intended to solve the above-mentioned problem by laminating a PET sheet containing a special component as a surface layer. However, it cannot be said that the slipperiness of the surface is sufficiently solved by such a method.

[0008]

DISCLOSURE OF THE INVENTION As a result of intensive studies made by the present inventors in order to solve such conventional problems, as a result, the polyester was blended with a specific amount of inert particles, and an aliphatic alcohol and a fat were added. It has been found that by adding a specific ester compound composed of a group monocarboxylic acid, excellent slipperiness, scratch resistance, cuttability and adhesiveness can be imparted without impairing the transparency which is the characteristic of A-PET. The present invention has been completed.

[0009]

That is, according to the present invention, firstly, (A) terephthalic acid as a main acid component, 10 to 90 mol% of ethylene glycol and 90 to 10 mol% of 1,4-cyclohexanedimethanol. (Hereafter, this is 1,
4-CHDM) as a glycol component and 10 to 5000 pp of inert particles having an average particle size of 0.5 to 30 μm.
m and a skin layer composed of a copolyester containing 0.1 to 5% by weight of an ester compound composed of an aliphatic alcohol and an aliphatic monocarboxylic acid and having a total carbon number of 30 to 60, and (B) terephthalic acid. A multilayer sheet composed of a core layer made of polyester having ethylene glycol as a main glycol component as a main acid component, wherein the skin layer is laminated on at least one side of the core layer, and the thickness of all skin layers is 3 for all seat layers
˜50% and the intrinsic viscosity of all layers of the sheet is 0.5˜
The polyester multilayer sheet is 1.1.

The second invention uses terephthalic acid as a main acid component as the skin layer (A), and contains 10 to 90 mol% of ethylene glycol and 90 to 10 mol% of 1,4-CHD.
M is a glycol component and the average particle size is 0.5 to 10 μm
10 to 5000 ppm of inactive particles, the average particle size is 10
A copolyester containing 5 to 1500 ppm of inactive particles of -30 μm and 0.1 to 5% by weight of an ester compound composed of an aliphatic alcohol and an aliphatic monocarboxylic acid and having a total carbon number of 30 to 60 is used. The above-mentioned first polyester multilayer sheet.

A third invention is a polyester container obtained by cutting, punching, bending, adhering and assembling the polyester multilayer sheet of the first or second invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The polyester used in the core layer (B) of the present invention is not only homo-PET but also a part of the terephthalic acid component is isophthalic acid, adipic acid, diphenylcarboxylic acid, diphenyletherdicarboxylic acid, sebacic acid, naphthalenedicarboxylic acid. And / or a part of the ethylene glycol component is replaced with diethylene glycol, hexamethylene glycol, trimethylene glycol, propylene glycol, cyclohexanedimethanol, neopentyl glycol, butylene glycol. Also included are copolyesters substituted with one or more other glycol components such as

The polyester may contain a trifunctional or higher-functional compound or a monofunctional compound as a polymerization component in a range considered to be substantially linear. Further, a heat stabilizer, a fluidity improver, an ultraviolet absorber, an antistatic agent, an antifogging agent and the like can be added to the polyester within a range that does not reduce the transparency. Further, when matting is required, a coloring agent such as titanium dioxide, calcium carbonate, iron oxide or carbon black can be contained.

The sheet thickness used in the present invention is not particularly limited, but is usually 50 to 1500 μm, preferably 1
It is 00 to 500 μm.

The intrinsic viscosity of the polyester multilayer sheet of the present invention is required to be 0.5 to 1.1. If it is less than 0.5, the original impact strength of the polyester sheet decreases, and if it exceeds 1.1. Not only is it less economical, but melt extrusion during sheet production becomes difficult.

The copolyester used as the skin layer (A) in the present invention contains terephthalic acid as a main acid component, 10 to 90 mol% of ethylene glycol and 90 to 1 mol%.
It is composed of a glycol component consisting of 0 mol% 1,4-CHDM. The copolymer component used has excellent adhesion,
Further, 1,4-CHDM is required from the viewpoint that excellent impact properties, particularly impact properties after aging, can be imparted.
1,4-CHDM is less than 10 mol% or 90 mol%
If it exceeds, not only the adhesiveness is poor, but also the compatibility with the ester compound used in the present invention is lowered and the transparency is impaired. Further, various dicarboxylic acid components and / or various glycol components may be copolymerized within a range that does not impair the physical properties of the polymer.

The inert particles used in the present invention are fine particles which are inert to the polyester synthesis reaction system, and specifically, silica, calcium carbonate, aluminum silicate, barium sulfate, calcium phosphate, talc, titanium dioxide, water. There are fine powders of aluminum oxide, calcium terephthalate, calcium silicate, fluorine-containing fine particle polymers, crosslinked polystyrene polymers and the like.

These inert particles may be used alone or in combination of two or more kinds. In order to disperse uniformly in the sheet, a method of adding it as a slurry at the time of polymerization, or melting and kneading the inert particles and the resin to form a master batch in advance, and use this master batch in the presence of inert particles during sheet production For example, a method of supplying an extruder such that the amount becomes a predetermined value is used. Also, within the range that does not reduce the transparency of the sheet, olefin wax and fatty acids,
The surface treatment of the inert particles may be performed with a metal salt of fatty acid or the like.

In the present invention, the resin (A) used for the skin layer contains 1 part of inert particles having an average particle size of 0.5 to 30 μm.
It is characterized by adding 0 to 5000 ppm. If the content of the inert particles is less than 10 ppm, the slipperiness is insufficient, and if it exceeds 5000 ppm, the transparency is impaired. If further good slipperiness and transparency are required, the inert particles having an average particle size of 0.5 to 10 μm should be used in an amount of 10 to 5000 p.
pm, the average particle diameter is 10 to 30 μm
It is preferable to use 0 ppm or less. By using such two types of inert particles in combination, a sheet having excellent slipperiness and scratch resistance can be obtained as compared with the case of using only one type of inert particles.

In the present invention, it is important to use 0.1 to 5% by weight of an ester compound composed of an aliphatic alcohol and an aliphatic monocarboxylic acid and having a total of 30 to 60 carbon atoms. The aliphatic alcohol constituting the ester compound preferably has 6 or more carbon atoms, and includes, for example, lauryl alcohol, myristyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, nonadecyl alcohol, eicosyl alcohol,
Examples thereof include, but are not limited to, behenyl alcohol, ceryl alcohol, melissyl alcohol and the like.

The aliphatic monocarboxylic acid constituting the above ester compound is preferably one having 10 or more carbon atoms, for example myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, montan. Examples thereof include acids and melissic acid, but are not limited thereto.

The total number of carbon atoms of the aliphatic alcohol and the aliphatic monocarboxylic acid used in the present invention is 30 to 60.
As the individual ester compound, the above-mentioned aliphatic alcohol and aliphatic monocarboxylic acid can be appropriately selected and combined. Specific examples include lauryl stearate, stearyl stearate, lauryl melissate, behenyl behenate, and ceryl mericate. When the ester compound has less than 30 carbon atoms, the heat resistance becomes insufficient during the production of the polyester multilayer sheet, which causes decomposition and makes film formation difficult. On the other hand, if the number exceeds 60, the compatibility with the copolyester decreases and the transparency is impaired. If the blending amount is less than 0.1% by weight, the amount of bleed-out on the surface of the sheet will be small and sufficient slipperiness will not be obtained. If the blending amount exceeds 5% by weight, the amount of bleed-out on the surface of the sheet is too large, resulting in poor adhesion and transparency.

As a method of adding the above-mentioned ester compound, a known method can be applied and there is no particular limitation. For example, there is a method of forming a pellet as a master batch in advance and supplying it at the time of extrusion, a method of adding at the time of polymerization and the like.

The layer ratio of the polyester multilayer sheet of the present invention is such that the thickness of all skin layers is 3 to 5 with respect to all layers of the sheet.
It is essential that it is 0%. If it is less than 3%, it becomes difficult to form a uniform skin layer during the production of the sheet, and if it exceeds 50%, not only the economic efficiency is lowered but also the transparency is impaired.

When the polyester multilayer sheet of the present invention is formed into a film, it can be produced by known techniques such as melt lamination, coextrusion and dry lamination, but the coextrusion method is preferred from the viewpoint of sheet quality. Further, the multilayer sheet obtained by the coextrusion method can be obtained by melt-extruding with a usual extruder for polyester such as a twin-screw vent type extruder and cooling the molten resin with a cooling drum. The sheet is preferably quenched as much as possible in order to prevent a decrease in transparency due to crystallization, and the crystallinity is preferably 10% by weight or less (density 1.348 g / cm ³ or less) and the sheet haze is preferably 5% or less.

Further, as a film forming method, there are a method of sandwiching between metal rolls for cooling (touch roll method), an electrostatic application method, an air knife method, etc., but the touch roll is used in terms of glossiness and uniformity of thickness of the sheet. Method is preferred.

In-line recycling is carried out by crushing the ears that appear when the sheet is cut into a predetermined width during film formation and the skeletons that appear when punching the product and returning it as a raw material.
Although generally used in ET, such a method can be used in the present invention as long as the intrinsic viscosity of the sheet is not extremely lowered.

The sheet thus obtained can be made into a clear case by cutting, punching, bending, adhering and assembling it by an ordinary method.

[0029]

EFFECTS OF THE INVENTION According to the present invention, the slipperiness during sheet cutting, the blocking property between sheets and the scratching property when the sheet is made into a product while maintaining the transparency of A-PET are improved. It is most suitable for improving the blocking resistance of polyester containers obtained by cutting, punching, bending, adhering, and assembling the sheet, or thermoforming products.

[0030]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.
In addition, each characteristic value was measured according to the following method.

(1) Intrinsic Viscosity A phenol / tetrachloroethane mixed solvent having a weight ratio of 60/40 was used and measured at a concentration of 1.0 g / dl and at 20 ° C.

(2) Sheet haze Using a haze meter NDH-20D manufactured by Nippon Denshoku Co., Ltd., the haze (fogging value) of the sheet was measured by a method according to JIS-K-7105.

(3) Static friction coefficient Using a friction measuring machine TR type manufactured by Toyo Seiki Co., Ltd., ASTM
The static friction coefficient of the sheet was measured by a method according to -1894.

(4) Cutability 50 sheets having a length of 200 mm and a width of 200 mm were stacked, and the sheets were pressed with a Thomson blade and evaluated. Number of cut sheets 41 to 50 ○ 21 to 40 △ 0 to 20 ×

(5) Scratchability After measuring the static friction coefficient, a sample was used JIS-K-7105 using a haze meter NDH-20D manufactured by Nippon Denshoku Co., Ltd.
The haze (haze value) of the sheet was evaluated according to the above. Haze less than 3.5% ○ 3.5% or more Poor.

(6) Solvent Adhesiveness Sheets are adhered using cyclohexanone according to JIS-K-
The peel strength was measured by the method according to 6772. Peel strength Over 2000 g / 15 mm ○ 2000 to 500 g / 15 mm △ Less than 500 g / 15 mm ×

(7) Average particle size MULTI made by Coulter Electronics Limited
The diameter (particle diameter) at an integrated volume fraction of 50% in the equivalent spherical distribution measured by the Sizer apparatus was defined as the average particle diameter.

Examples 1 to 6 and Comparative Examples 1 to 13 Poly 1,4-cyclohexane dimethylene terephthalate resin having an intrinsic viscosity of 0.70 was dried to a water content of 200 ppm or less, and then dried at 240 ° C. by a biaxial kneader. The inert particles having the particle size shown in Table 1 were melt-kneaded to prepare a 10% by weight masterbatch. Similarly, 10 of the ester compounds of the aliphatic alcohol and the aliphatic monocarboxylic acid shown in Table 1
A wt% masterbatch was made. Next, using a twin-screw vented extruder, the vacuum degree at the vent part was 285 ° C. and 5 mmHg.
When performing multi-layer melt extrusion from the T-die under the conditions described above to form a film by the touch roll method, each masterbatch of these inert particles and ester is added to the copolyester resin shown in Table 1 in a predetermined amount. Then, a multilayer sheet having a three-layer structure and a thickness of 250 μm and having the composition shown in Tables 1 and 2 was produced. The physical properties of these sheets are shown in Table 3.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

Claims (3)

[Claims] 1. A main component of (A) terephthalic acid, 10 to 90 mol% of ethylene glycol and 90
10 mol% of 1,4-cyclohexanedimethanol as a glycol component, 10 to 5000 ppm of inert particles having an average particle size of 0.5 to 30 μm, and the total number of carbon atoms consisting of an aliphatic alcohol and an aliphatic monocarboxylic acid. Is 30
A skin layer made of a copolyester containing 0.1 to 5% by weight of 60 ester compounds, and (B) a core layer made of a polyester containing terephthalic acid as a main acid component and ethylene glycol as a main glycol component, And a skin layer laminated on at least one side of the core layer, the thickness of all skin layers is 3 to 50% of the total thickness of the sheet, and A polyester multi-layer sheet having a viscosity of 0.5 to 1.1. 2. The skin layer (A) contains terephthalic acid as a main acid component, 10 to 90 mol% ethylene glycol and 90 to 10 mol% 1,4-cyclohexanedimethanol as a glycol component, and has an average particle size of 0.5-10
10 to 5000 ppm of inactive particles of μm, 1500 ppm or less of inactive particles having an average particle size of 10 to 30 μm, and an ester compound having a total carbon number of 30 to 60 consisting of an aliphatic alcohol and an aliphatic monocarboxylic acid are 0. 1 ~
The polyester multilayer sheet according to claim 1, wherein the polyester multilayer sheet comprises 5% by weight of copolyester. 3. A polyester container obtained by cutting, punching, bending, adhering and assembling the polyester multilayer sheet according to claim 1 or 2.