JPH0747646B2 - Matte heat shrink film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a matte heat shrinkable film, particularly a matte of vinyl chloride resin useful as a label for various containers, a cap seal, a packaging material for an integrated product, and the like. Heat-shrinkable film.

(Prior Art) Conventionally, a “film or tube” of a heat-shrinkable vinyl chloride-based resin (in all other places except the examples in the text, this is simply the meaning of “film”).
Compared with other resin materials, is superior in transparency and gloss, has good chemical resistance, water resistance, printability, etc., and can be heat-sealed, so it can be used for everything from foods to machine parts. Widely used as various packaging materials for
It has also been applied to labels and cap seals.

(Problems to be solved by the invention) Recently, matte heat shrinkage has been demanded in order to enhance the image of a product so that it has a better appearance than other products of the same kind. Commercialization of films is desired.

Conventionally, as a means for matting the surface of a heat-shrinkable film, 1) a method of polishing with sandblast, sandmat, etc .; 2) a method of adding an inorganic filler having an average particle size of 1.0 to 4.0 μm and a maximum particle size of 10 μm or less; ) A method of processing with an embossing roll at the stage of extruding or calendering the sheet before stretching;

However, since the method 1) mechanically scratches the film to make it matte, it may impair the physical properties of the film itself, and an additional polishing step may increase the manufacturing cost. Inevitable. In order to obtain a sufficient matting effect by the method 2), it is necessary to add a large amount of an inorganic filler, and as a result, the film may be broken during printing of the film, processing such as bag making, or pinholes during printing (printing). Omission) occurs. In the method of 3), it is difficult to obtain a matte film having a fine texture because the sheet embossed with a satin squeezing roll is stretched in the subsequent process, and the degree of matteness of the heat-shrinkable film depends on the application. When it is desired to make adjustments, it is necessary to prepare a plurality of embossing rolls suitable for each of them in advance, so that an increase in cost cannot be avoided and it is economically disadvantageous.

In order to overcome these disadvantages, a surface-matted heat-shrinkable film formed by molding and stretching a composition mainly composed of a partially crosslinked vinyl chloride resin has been proposed (Japanese Patent Application Laid-Open No. 2004-242242). However, in addition to the drawbacks such as poor extrusion processability and poor long-run property,
Since the limit of the draw ratio at the time of stretching is 2.2 times, there was a problem that the heat shrinkage ratio at 100 ° C. could not be 50% or more, and the application was restricted.

Therefore, the object of the present invention is to provide a glossy material that does not impair the physical properties of the film by mechanical means or addition of a non-film material, causes an increase in equipment costs, and is not restricted by the molding processability. It is an attempt to obtain a heat-shrinkable film having a uniform eraser surface roughness and excellent printability.

(Means for Solving the Problem) The present invention provides, as the matte heat-shrinkable film,
For the partially cross-linked vinyl chloride resin as the component (A) and the non-cross-linked vinyl chloride resin as the component (B), the average degree of polymerization of each THF-soluble component is (B). The average degree of polymerization of the component-the average degree of polymerization of the component (A) ≧ 100, and the mixing ratio of both components is (A) / (B) = 15 / 85-80 / 20 by weight. The mixing ratio of vinyl resin is (A) / (B) = 15 / 85-80 / 20 by weight.
The gist is that the vinyl chloride resin composition is formed and stretched.

Hereinafter, the present invention will be described in detail.

First, the partially crosslinked vinyl chloride resin used as the component (A) in the present invention is, for example, JP-B-62-62.
-15564, JP-A-54-134793, etc., a vinyl chloride monomer or a mixture of vinyl chloride as a main component with another monomer is subjected to a suspension polymerization method or the like. It can be produced by allowing a polyfunctional monomer in an amount corresponding to the desired degree of crosslinking to be present in the polymerization system during the polymerization.

This polyfunctional monomer is a monomer having two or more ethylenic double bonds in the molecule.
Diallyl esters of phthalic acid such as cereal phthalate; Diallyl esters of ethylenically unsaturated dibasic acid such as diallyl maleate, diallyl fumarate, diallyl itaconate; diallyl ether, triallyl cyanurate, ethylene glycol divinyl ether, n And divinyl ethers such as butanediol divinyl ether; diacryl or dimethacryl esters of polyhydric alcohols such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate and polyethylene glycol dimethacrylate;

The amount of these polyfunctional monomers used is, in order to achieve the object of the present invention to obtain a heat-shrinkable film having excellent mattness on the surface,
It is desirable to add 0.01 to 10 parts by weight to 100 parts by weight of a vinyl chloride monomer or a mixture of vinyl chloride as a main component and another monomer.

Other vinyl monomers copolymerized with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid esters such as methyl acrylate and ethyl acrylate; methyl methacrylate, Examples thereof include methacrylic acid esters such as ethyl methacrylate, olefins such as ethylene and propylene, maleic anhydride, acrylonitrile, styrene, vinylidene chloride and the like.

The partially crosslinked vinyl chloride resin as the component (A) thus obtained preferably has a gel content insoluble in tetrahydrofuran of 5 to 50% by weight, more preferably 10 to 35% by weight. Especially, the amount of 15 to 25% by weight is preferable. If it is less than 5% by weight, a good matte effect cannot be obtained, and if it exceeds 50% by weight, it becomes difficult to process and mold the film, and more fish eyes are generated during film stretching, which causes pinholes during printing. It is not preferable because it causes

Further, the average degree of polymerization of the portion dissolved in tetrahydrofuran is 400 to 1000, preferably 500 to 800, and if this is less than 400, the physical properties of the heat-shrinkable film are deteriorated, and printing, slits, bag making, etc. It causes film breakage during post-processing, and if it exceeds 1000, extrudability,
This is not preferable because the stretchability is significantly deteriorated.

On the other hand, the non-crosslinked vinyl chloride resin used as the component (B) in the present invention has a property of being completely dissolved in tetrahydrofuran, and can be obtained by a usual method such as a suspension polymerization method.

This includes not only vinyl chloride homopolymers but also copolymers of vinyl chloride as a main component with vinyl chloride and other copolymerizable monomers.

As other monomers copolymerizable with vinyl chloride,
For example, vinyl acetates such as vinyl acetate and vinyl propionate; acrylic acid esters such as methyl acrylate and ethyl acrylate; methacrylic acid esters such as methyl methacrylate and ethyl methacrylate; ethylene and propylene Olefin: Maleic anhydride, acrylonitrile, styrene, vinylidene chloride and the like can be mentioned.

The average degree of polymerization of this non-crosslinked vinyl chloride resin is 600 to 1,100, preferably 700 to 900, and if it is less than 600, the physical properties of the resulting heat-shrinkable film deteriorate, and Film breakage easily occurs,
Further, if it exceeds 1,100, extrusion processability, stretchability, etc. are deteriorated, which is not preferable.

The matte heat-shrinkable film according to the present invention comprises a partially crosslinked vinyl chloride resin as the component (A),
The main raw material is a vinyl chloride resin composition comprising a non-crosslinked vinyl chloride resin as the component (B). The mixing ratio of both resin components in this composition is ( It is necessary that A) / (B) = 15/85 to 80/20, preferably 30/70 to 60/40. This is 15/85
When it is less than 80%, a good matte effect cannot be obtained, and the uniformity of the surface roughness is poor. When it exceeds 80/20, the extrudability is deteriorated and the draw ratio cannot be increased.

This resin composition also has a THF-insoluble gel component (A),
It is desirable that the total amount of both components (B) is 3 to 18% by weight, more preferably 7 to 15% by weight. If it is less than 3% by weight, a good matting effect cannot be obtained, and if it exceeds 18% by weight, the fish eyes of the film increase and the pinholes at the time of printing increase.

TH in the above (A) and (B) vinyl chloride resin components
The average degree of polymerization of the F-soluble component is: the average degree of polymerization of the component (B)-
It is necessary that the average degree of polymerization of the component (A) be 100 or more, and if it is within this range, the surface roughness of the obtained heat-shrinkable film of the present invention becomes more uniform, and at the time of printing. It is possible to prevent the occurrence of uneven printing.

The resin composition may also contain 0 to 20 parts by weight of a plasticizer such as DOA, DOP and TPP per 100 parts by weight of the resin. If it exceeds 20 parts by weight, the resulting heat-shrinkable film becomes too soft, and when it is used as a label or the like, it becomes difficult to mount the heat-shrinkable film on a container or a bottle and productivity is lowered, which is not preferable.

Further, if necessary, the resin composition, MBS, EVA,
Impact modifiers such as ABS, processing aids such as MMA, dibutyltin malate ester, dioctyltin malate polymer, tin stabilizers such as dioctyltin mercaptide, Ca
-Zn-based metal soap stabilizers, butyl stearate,
Monostearyl glyceride, ethylene bisamide,
A lubricant such as polyethylene wax, an ultraviolet absorber, a colorant, an antistatic agent and the like can be added as appropriate.

This resin composition, extrusion molding, after molding into a film shape by a known molding method such as calender molding, depending on the intended use, by means such as lateral uniaxial stretching, longitudinal uniaxial stretching, or longitudinal and transverse biaxial stretching, The matte heat-shrinkable film according to the present invention having a heat shrinkage ratio at 100 ° C. of 50% or more can be obtained by stretching at a stretch ratio of 2.3 to 4.0 in at least one uniaxial direction.

Hereinafter, specific embodiments of the present invention will be described with reference to Examples.
The present invention is not limited to the description of the examples without departing from the scope of the invention. In the examples,
Nos. 7 and 8 are the present invention, and Nos. 1 to 6 are comparative examples.

(Example) Eight types of compounds (Experiment No. 1 to 8) shown in the following table were mixed using a high speed mixer, heated to 140 ° C., then cooled,
Created each compound.

The details of each component used in this formulation are as follows.

Partly cross-linked vinyl chloride resin GR-800S as component (A): manufactured by Shin-Etsu Chemical Co., Ltd., gel content 20.0%, average degree of polymerization 780 of THF-soluble content.

GR-600S: manufactured by Shin-Etsu Chemical Co., Ltd., gel content 21.0%, average degree of polymerization 580 of THF-soluble content.

Non-crosslinked vinyl chloride resin TK-800 as component (B): manufactured by Shin-Etsu Chemical Co., Ltd., gel content 0%, average degree of polymerization of THF-soluble content 800.

-Impact modifier Kane Ace B-22: MBS resin manufactured by Kanebuchi Chemical Co., Ltd.

-Processing Aid PA-20: Kanafuchi Chemical Co., Ltd. MMA resin.

Stabilizer TS-209S: Akishima Chemical Co., Ltd. organotin stabilizer.

・ Lubricant Calcol 86: manufactured by Kao Soap Co., Ltd.

Alflo H-100S: manufactured by NOF CORPORATION.

[Evaluation of extrusion processability]

For these 8 compounds, using a 50 mmφ single extruder, cylinder temperature C ₁ : 145 ° C., C ₂ : 175 ° C., adapter temperature A: 150 ° C., die temperature D: 190 ° C., screw compression ratio CR: 3.0 The same L / D: 22, the same number of revolutions: 20 rpm, under extrusion conditions, a T-die sheet having a thickness of 0.2 mm and a width of 500 mm is extruded, and the motor load current, extrusion amount, and long-run property at that time are measured. The extrudability of each sample was evaluated.

The long-run property was evaluated as × when the FE (yellow to reddish brown) generation time was within 12 hours, Δ when 12 to 24 hours, and ○ when 24 hours or more.

[Evaluation of stretchability]

Thickness 0.2mm, width 500mm obtained in the above extrusion experiment
Each of the T-die sheets in (1) was stretched 2.5 times at a preheating temperature of 100 ° C., a stretching temperature of 90 ° C., a heat setting temperature of 90 ° C. and a line speed of 15 m / min using a small stretching machine to obtain a heat shrinkable film.

At the time of this stretching, a sheet that could be stretched 2.5 times was evaluated as ◯, and a sheet that could not be drawn was evaluated as x, and the sheet stretchability was evaluated.

[Evaluation of heat shrink film]

Each heat shrink film (experiment
For No. 1 only, stretched 2.2 times), the film turbidity (haze), the matteness of the surface, the uniformity of the roughness of the matte surface, and the shrinkage ratio were measured by the following methods. The thickness of printing ink on heat shrink film is about 1-2
Gravure printing on the entire surface (solid printing) on the cooling surface of the heat-shrinkable film extruded to a thickness of about μm, and the appearance of the matte surface and the number of pinholes (number /
The heat shrink film was evaluated by making a measurement of m ² ).

・ Film turbidity (hase): According to JIS K-7105, turbidity meter (Nippon Denshoku Co., Ltd.)
Manufactured).

・ Matteness of the surface (evaluation standard): The surface is matte and has a deep astringent texture ...
◎ ◎ Matte …… ○ Surface has a little gloss …… △ The entire surface has a gloss …… × ・ Matted surface roughness uniformity (evaluation standard): Surface roughness is fine Uniform ・ ・ ・ ◎ Surface roughness is uniform …… ○ Surface roughness is uneven and unevenness is observed …… △ Surface is smooth …… × ・ Matte surface appearance (evaluation criteria) ): The printing ink is printed uniformly and evenly .... ◎ There is some printing ink unevenness .... ○ Printing ink unevenness is noticeable. (Effects of the Invention) The matte heat-shrinkable film according to the present invention has good extrusion processability as compared with the conventional one, even though it contains a partially crosslinked vinyl chloride resin in its component. Thus, the long-run property is also improved and the draw ratio of 2.5 times or more is secured, so that the heat shrinkage at 100 ° C becomes 50% or more. In addition, the roughness of the matte surface is uniform, and it is possible to prevent uneven printing during printing.

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Claims (1)

[Claims] 1. An average degree of polymerization of THF-soluble components of a partially crosslinked vinyl chloride resin as the component (A) and an uncrosslinked vinyl chloride resin as the component (B). Where (B) component has an average degree of polymerization- (A) component has an average degree of polymerization of ≧ 100, and the mixing ratio of both components is (A) / (B) = 15 / 85-80. A matte heat-shrinkable film formed by molding and stretching a vinyl chloride resin composition of / 20.