JPH0374438A - Matte heat-shrinkable film - Google Patents

Abstract

PURPOSE:To obtain the subject film, excellent in extrusion processability and long runnability and useful as labels, etc., of containers by molding, drawing and processing a mixture composed of a partially crosslinked vinyl chloride- based resin with an uncrosslinked vinyl chloride-based resin in a specific proportion. CONSTITUTION:The objective film obtained by molding, drawing and processing a vinyl chloride-based resin composition composed of (A) a partially crosslinked vinyl chloride-based resin (preferably having 15-25wt.% content of a gel portion insoluble in THF) and (B) an uncrosslinked vinyl chloride-based resin (preferably having 700-900 average polymerization degree) at (15/85)-(80/20), preferably (30/70)-(60/40) mixing weight ratio of the components (A/B).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a matte heat-shrinkable film and a polyvinyl chloride-based resin useful as labels for various containers, cap seals, packaging materials for aggregates, etc. It relates to a matte heat shrinkable film.

(Prior art) Conventionally, heat-shrinkable vinyl chloride resin "films or tubes" (in other parts of the text where examples are discussed, "films" are simply referred to have this meaning). Compared to other resin materials, it has excellent transparency and gloss, has good chemical resistance, water resistance, printability, etc., and can be heat-sealed, so it can be used in various products ranging from foods to mechanical parts. In addition to being widely used as a packaging material, it has also been applied to labels, cap stickers, etc.

(Problem to be Solved by the Invention) Recently, due to the desire to upscale the image of products and to have better appearance and texture than other similar products, matte heat shrinkable Commercialization of the film is desired.

Conventionally, methods for matting the surface of a heat-shrinkable film include: 1) polishing by sandblasting, sand matting, etc.; 2) average particle size of 1.0 to 4.0μ, maximum particle size of 10. The following methods of adding an inorganic filler; 3) A method of processing the sheet with an embossing roll at the stage of extrusion molding or calender molding of the sheet before stretching; and the like are known.

However, method 1) mechanically scratches the film to make it matte, which may damage the physical properties of the film itself, and increases production costs due to the additional polishing process. Inevitable. In order to obtain a sufficient matting effect using method 2), it is necessary to add a large amount of inorganic filler, which results in film breakage during processing such as film printing and bag making, and pinholes during printing. Method 3) involves stretching the embossed sheet with a satin pattern roll in the subsequent process, which makes it difficult to obtain a matte film with a fine texture, and also makes it difficult to obtain a matte film with a fine texture. When it is desired to adjust the degree of matteness depending on the application, it is necessary to prepare a plurality of embossing rolls suitable for each in advance, which inevitably increases costs and is economically disadvantageous.

To overcome these disadvantages, compositions based on partially crosslinked vinyl chloride resins.

A heat-shrinkable film with a matte surface formed by molding and stretching has been proposed (Japanese Unexamined Patent Publication No. 118226/1983).
However, this method has disadvantages such as poor extrusion processability and poor long-run properties, and since the stretching ratio is limited to 2.2 times, the heat shrinkage rate at 100°C must be 50% or more. There was a problem in that it was not possible to do so, and its uses were restricted.

Therefore, the object of the present invention is to prevent the physical properties of the film from being impaired by mechanical means or the addition of non-film materials, or to increase equipment costs.

Furthermore, there are no restrictions on moldability.

You are trying to get a matte heat shrink film.

(Means for Solving the Problems) The present invention provides this matte heat shrinkable film (
The mixing ratio of partially crosslinked vinyl chloride resin as component A) and vinyl chloride resin that is not crosslinked as component (B) is (A)/(B) = 15 by weight.
/85 to 80/20 A vinyl chloride resin composition is molded and stretched.

The present invention will be explained in detail below.

First, the partially crosslinked vinyl chloride resin used as component (A) in the present invention is, for example,
As disclosed in Japanese Patent Application Laid-open No. 2-15564 and Japanese Patent Application Laid-open No. 134793/1984, vinyl chloride monomer or a mixture of vinyl chloride and other monomers mainly composed of vinyl chloride is subjected to suspension polymerization. It can be produced by allowing a polyfunctional monomer to exist in an amount corresponding to the desired degree of crosslinking in the polymerization system.

This polyfunctional monomer is a monomer having two or more ethylenic double bonds in the molecule, and includes, for example,
Diallyl esters of phthalic acid such as diallyl phthalate; diallyl maleate.

Diallyl esters of ethylenically unsaturated dibasic acids such as diallyl fumarate and diallylitaconate; divinyl ethers such as diallyl ether, triallyl cyanurate, ethylene glycol divinyl ether and n-butanediol divinyl ether; ethylene glycol diacrylate , ethylene glycol dimethacrylate,
Examples include diacrylic or dimethacrylic esters of polyhydric alcohols such as polyethylene glycol diacrylate and polyethylene glycol dimethacrylate.

The amount of these polyfunctional monomers to be used is determined to achieve the objective of the present invention to obtain a heat-shrinkable film with an excellent matte surface.
Mainly vinyl chloride monomer or vinyl chloride. per 100 parts by weight of a mixture of this and other monomers, 0.01-
The amount is preferably 10 parts by weight.

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

The partially crosslinked vinyl chloride resin as component (A) thus obtained preferably has a gel content insoluble in tetrahydrofuran of 5 to 50% by weight,
Furthermore, 10 to 35% by weight, especially 15 to 25% by weight
If it is less than 5% by weight, a good matting effect cannot be obtained, and if it exceeds 50% by weight, it will be difficult to process and form the film, and there will be a lot of fins during film stretching ( This is not preferable because it causes pinholes to occur during printing.

Moreover, the average degree of polymerization of the portion dissolved in the above-mentioned tetrahydrofuran is 400 to 1000. Preferably SOO~800
If it is less than 400, the physical properties of the heat-shrinkable film will deteriorate, causing film breakage during post-processing such as printing, slitting, and bag making, and if it exceeds 1000, extrusion processability and stretchability will deteriorate significantly. Therefore, it is not desirable.

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

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

In addition, other monomers that can be copolymerized with vinyl chloride include 1
For example, vinyl esters such as vinyl acetate and vinyl propionate; acrylic esters such as methyl acrylate and ethyl acrylate; methacrylic esters such as methyl methacrylate and ethyl methacrylate; Olefins: maleic anhydride, acrylonitrile, styrene, vinylidene chloride, etc.

The average degree of polymerization of this non-crosslinked vinyl chloride resin is SOO~1,100. Preferably, the number is between 700 and 900; if it is less than 600, the physical properties of the resulting heat-shrinkable film will deteriorate, making it more likely that the film will break during processing, while if it is more than 1,000, the extrusion processability will deteriorate. It is not preferable because stretchability etc. deteriorate.

The matte heat-shrinkable film according to the present invention includes a partially crosslinked vinyl chloride resin as the component (A), and (
The main raw material is a vinyl chloride resin composition consisting of a non-crosslinked vinyl chloride resin as component B), and the blending ratio of both resin components in this composition is (A) by weight. )/(B) = 15/85~80
/20. Preferably, it is necessary to set the ratio to 30/70 to 60/40. If this ratio is less than 15/85, a good matting effect cannot be obtained and the uniformity of the surface roughness becomes poor, and if it exceeds 80/20, extrusion processability deteriorates and the stretching ratio cannot be increased.

This resin composition also has a THF-insoluble gel content A)
, (B) desirably 3 to 20% by weight, more preferably 7 to 17% by weight based on the total weight of both components; if it is less than 3% by weight, a good matting effect cannot be obtained; If it exceeds %, fisheyes in the film will increase, leading to an increase in pinholes during printing.

T in both vinyl chloride resin components (A) and (B) above
The average degree of polymerization of HF-soluble matter.

[Average degree of polymerization of component (B) - [Average degree of polymerization for (A) 12 minutes) ≦0, preferably (Average degree of polymerization of component (B)) - (Average degree of polymerization of component (A)) 5100 It is desirable that the ratio be within this range, so that the resulting heat-shrinkable film of the present invention will have a more uniform surface roughness, and the occurrence of printing unevenness during printing can be prevented.

This resin composition also contains 0 to 2 parts by weight per 100 parts by weight of resin.
0 parts by weight of plasticizers such as DOA, DOP, TPP can be added. If the amount exceeds 20 parts by weight, the resulting heat-shrinkable film becomes too soft, making it difficult to attach it to a container or bottle when used as a label, resulting in a decrease in productivity, which is undesirable.

Furthermore, if necessary, the resin composition may include MBS, E
Impact modifiers such as VA and ABS, processing aids such as MMA, tin-based stabilizers such as diptyltin malate ester, dioctyltin malate polymer, dioctyltin mercaptide, and metal soap stabilizers such as Ca-Zn. A lubricant such as butyl stearate, monostearylglyceride, ethylene bisamide, polyethylene wax, an ultraviolet absorber 1 coloring agent, an antistatic agent, etc. can be added as appropriate.

This resin composition is formed into a film by a known forming method such as extrusion molding or calendar molding, and then subjected to horizontal uniaxial stretching, longitudinal-axial stretching, or longitudinal-horizontal biaxial stretching, depending on the purpose of use. .

The stretching ratio in at least one axis direction is 2.3 to 4.0
When stretched by 2 times, a matte heat-shrinkable film according to the present invention can be obtained which has a heat-shrinkage rate of 50% or more at 100°C.

Hereinafter, specific embodiments of the present invention will be explained with reference to Examples and Comparative Examples; however, the present invention is not limited to the description of each Example without departing from the gist thereof.

(Example) Eight types of formulations (Experiment Nos. 1 to 8) shown in Table 1 were mixed using a high-speed mixer, heated to 140°C, and then cooled to create respective flour pounds.

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

・Partially crosslinked vinyl chloride resin 0R-80O8 as component (A): manufactured by Shin-Etsu Chemical Co., Ltd., gel 920.0%
, average degree of polymerization of THF soluble content 780°G 5oos: Manufactured by Shin-Etsu Chemical Co., Ltd., gel content 21%
, average degree of polymerization of THF-soluble content: 580°. Non-crosslinked vinyl chloride resin TK-800 as component (B): Shin-Etsu Chemical MST, gel 90%.

Average degree of polymerization of THF soluble content: 800° ・Impact modifier Kane Ace B-22: Manufactured by Kanebuchi Chemical ■, MBS resin.

・Processing aids PA-20: Manufactured by Kanebuchi Kagaku ■, MMA resin.

・Stabilizer TS-209S: Manufactured by Akishima Chemical ■, organotin stabilizer.

・Lubricant Calcol 86: Manufactured by Kao Soap ■.

Alflow H-1003: Manufactured by NOF W@.

[Evaluation of extrusion processability]

These eight types of compounds were prepared using a 5 o ■ φ single extruder at cylinder temperature C: 145 °C;
,: 175℃, adapter temperature A: 150"C,
Die temperature D: 190℃, screw compression ratio CR:
3.0゜Same/D:22. Same rotation speed: 20 rpm under normal extrusion conditions.

The extrusion processability of each sample was evaluated by extruding a T-die sheet with a thickness of 0.2 cm and a width of 500 mm, and measuring the motor load current, extrusion amount, and long run property.

The long-run performance was evaluated as x when the occurrence time of discoloration FE (yellow to reddish brown) was within 12 hours, Δ for 12 to 24 hours, and 0 for 24 hours or more.

[Evaluation of stretchability]

Thickness 0.2 Peng obtained in the above extrusion experiment, Cap 5
For each T-die sheet of 00■, using a small stretching machine, the preheating temperature was 100℃, the stretching temperature was 90℃, and the heat setting temperature was 90℃.
The film was stretched 2.5 times at a line speed of 15 ml and 1 minute to obtain a heat-shrinkable film.

During this stretching, the stretchability of the sheet was evaluated, with those that were able to be stretched 2.5 times and those that could not be stretched as x.

[Evaluation of heat shrink film]

Obtained by the above stretching. For each heat-shrinkable film (experiment No. 1 only stretched 2.2 times), film turbidity (haze), surface matteness, uniformity of matte surface roughness, and shrinkage rate were measured using the following method. In addition, gravure printing was performed on the entire surface (solid printing) in gold on the cooling surface during sheet extrusion of the heat-shrinkable film so that the printing ink was approximately 1 to 2p thick on each heat-shrinkable film. The heat-shrinkable film was evaluated by measuring the appearance of the matte surface and the number of pinholes (number/d).

・Film turbidity (haze): Measured using a turbidity meter (Nippon Denshoku ■I) according to JIS K-7105.

・Surface matteness (evaluation criteria): The surface is matte and has a deep astringent texture.・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・O Matted・・・・・・
・・・・・・・・・・・・・・・・・・・・・ 0 There is some gloss on the surface ・・・・・・・・・・・・・・・・・・・・・
...6 The entire surface is glossy...
・・・・・・・・・×・Uniformity of roughness of matte surface (evaluation criteria): Surface roughness is fine and uniform...0
The surface roughness is uniform...
・・・・・・0 Surface roughness is uneven and unevenness is observed・・・・・・・・・・・・Δ Surface is smooth・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・×・Outer R of matte surface (evaluation criteria): Printing ink is printed evenly and evenly...
・・・・・・・・・O Printing ink is slightly uneven ・・・・・・・・・・・・
0 The unevenness of printing ink is noticeable...
・Δ (Effect of the invention) Although the matte heat-shrinkable film according to the present invention contains a partially crosslinked vinyl chloride resin in its components, it has better extrusion processability than conventional ones. is good, long-run properties are improved, and a stretching ratio of 2.5 times or more is ensured, so that the heat shrinkage rate at 100° C. is 50% or more.

hand Continued Supplementary Positive book (spontaneous) Heisei August 10, 2018

Claims (1)

[Claims] 1. The mixing ratio of partially crosslinked vinyl chloride resin as component (A) and non-crosslinked vinyl chloride resin B as component (B) is (A)/(B) by weight.
) = 15/85 to 80/20. A matte heat-shrinkable film formed by molding and stretching a vinyl chloride resin composition.