JPH0345671A - Plasticizer-resistant marking film - Google Patents

Abstract

PURPOSE:To lessen decrease in adhesive force and to get rid of swelling of a base film when the title film is applied to an adhered contg. a large amt. of a low mol.wt. plasticizer by combining a base film contg. a polyurethane and a pressure-sensitive adhesive layer contg. a specified acrylic pressure- sensitive adhesive. CONSTITUTION:The title film is formed of a base material consisting of a film contg. a polyurethane and an acrylic pressure-sensitive adhesive consisting of a vinyl monomer compsn. contg. an acrylic vinyl monomer and vinyl acetate. As the polyurethane, a non-yellowing polyurethane consisting of an aliph. isocyanate is pref. The thickness of the polyurethane film differs depending on the uses and a range of 20-200mum is pref. The content of vinyl acetate in the above-described, vinyl monomer compsn. is pref. in a range of 5-50wt.%.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a marking film used for advertising stickers, display stickers, etc., and in particular, a marking film containing a low molecular weight plasticizer with high migration properties. The present invention relates to a marking film in which the base film is not affected by a plasticizer and the adhesive strength is less reduced by the plasticizer when the marking film is applied to an adherend.

(Prior Art) Marking films include, for example, advertising stickers used for billboards, billboards, shutters, windows, etc.;
Decorative stripe stickers used on automobiles, motorcycles, motor boats, snowmobiles, etc.; traffic signs,
It is widely used for display stickers used on information boards and the like. Usually, these marking films are constructed by using a semi-rigid vinyl chloride resin as a base material, providing a suitable adhesive layer on one side of the base material, and further attaching a release paper on the adhesive layer.

In recent years, internally illuminated signboards, tents, flexible containers, truck hoods, etc. have been using low molecular weight compounds with high migration properties, such as phthalic acid plasticizers (dioctyl phthalate) (D
A vinyl chloride film containing a large amount of OP) is used alone, or in order to increase the strength, fibers coated with vinyl chloride resin or fibers laminated with a vinyl chloride film are used.

(Problems to be Solved by the Invention) However, when conventional marking films are applied to soft PVC sheets, PVC molded products, plastic products, etc. that contain large amounts of these highly migratable low molecular weight plasticizers, As the plasticizer migrates from these adherends over time, the adhesion strength decreases, and the peeling of the marking film and the occurrence of swelling and wrinkles due to the swelling of the base material caused by the migration of the plasticizer are unavoidable. .

The problem to be solved by the present invention is that even if a low-molecular-weight plasticizer that has a high migration property migrates from the adherend to the adhesive layer of the marking film and further to the surface substrate, the adhesive force will not decrease much. An object of the present invention is to provide a marking film in which the base material does not swell.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides (a) a base material made of a film containing polyurethane, and (b) a vinyl monomer composition containing an acrylic vinyl monomer and vinyl acetate. To provide a marking film having a pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive.

As a result of extensive research, the inventors of the present invention discovered that, in place of the conventional marking film based on a vinyl chloride resin film,
By creating a marking film made of a base material that retains the properties of a marking film and does not swell even when plasticizer transfers from the adherend, and an adhesive that does not reduce adhesive strength even when plasticizer transfers. The present invention has been completed.

As for the method for producing polyurethane used in producing the polyurethane-containing film used in the present invention, for example, in the preparation of polyurethane, a prepolymer is synthesized in advance from an isocyanate component and a polyol component in the presence or absence of a solvent. Examples include a method in which a high molecular weight polyurethane is then produced using a chain extender, or a method in which all components are reacted in one step to produce a polyurethane.

Furthermore, polymers whose main component is polyurethane and copolymerized and modified with vinyl chloride or acrylic monomers and other types of polymers, such as acrylic resins, methacrylic resins, As resins, ABS resins, plasticized vinyl chloride resins, epoxy resins, polycarbonates, polyesters, Blend polymers containing polyamide and the like can also be used as materials for the polyurethane-containing film used in the present invention.

Examples of the isocyanate component include aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and tolidine diisocyanate;
Examples include aliphatic diisocyanates such as xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, methylcyclohexyl diisocyanate, and dicyclohexylmethane diisocyanate, but marking films are required to have colorful colors and little change in color over time. Therefore, aliphatic diisocyanates that do not cause yellowing are particularly preferred. However, for marking films of dark colors such as black, where the yellowing of urethane does not affect much,
Aromatic diisocyanates can also be used.

Examples of the polyol component include polyether polyols such as polytetramethylene glycol and polypropylene glycol; dibasic acids such as succinic acid, adipic acid, cepacic acid, orthophthalic acid, and isophthalic acid; and ethylene glycol, propylene glycol, butylene glycol, and hexane glycol. Polyester diol with OH at the terminal obtained by esterification reaction of methylene glycol, etc.; polycaprolactone diol obtained by non-reaction of the above glycols and ε-caprolactone; poly(hexamethylene carbonate) diol; molecules such as polybutadiene glycol 1i500 ~3000 polymer diols, as well as their copolymers and modifications, can be used.

Furthermore, polyols such as ethylene glycol, butylene glycol, hexamethylene glycol, bishydroxyethoxybenzene, and trimethylolpropane; low molecular weight polyvalent compounds having functional groups reactive with isocyanates such as diamines such as isophorone diamine and xylylene diamine; can also be used.

Examples of the method for forming a polyurethane film include a casting method, a T-die method, a calendar method, and a blow molding method, among which the casting method and T-die method are preferred because of their good surface smoothness.

The thickness of the polyurethane film varies depending on the application, but is preferably in the range of 20 to 200 μm, and 25 to 100 μm.
A range of m is particularly preferred.

The adhesive used in the present invention is an acrylic adhesive obtained by radical polymerizing a vinyl monomer composition containing an acrylic vinyl monomer and vinyl acetate in a solution.

The content ratio of vinyl acetate in the vinyl monomer composition is 5
A range of io to 50% by weight is preferred, and a range of io to 40% by weight is particularly preferred. If the content of vinyl acetate is less than 5% by weight, the adhesive strength tends to decrease significantly, which is not preferable. If the content of vinyl acetate is more than 50% by weight, it is not preferable because the adhesive properties in a low temperature region tend to deteriorate and the weather resistance of the marking film tends to decrease.

Examples of acrylic vinyl monomers include (meth)
Acrylic acid; (meth)acrylic acid with 1 to 8 carbon atoms
alkyl or cycloalkyl ester; 2-hydroxyethyl (meth)acrylate, hydroxypropyl (
Functional group-containing acrylic acid esters such as meth)acrylate and glycidyl (meth)acrylate; (meth)acrylamide such as (meth)acrylamide and N-butoxymethyl (meth)acrylamide; (meth)acrylonitrile; and the like.

The content of the acrylic vinyl monomer in the vinyl monomer composition is preferably in the range of 50 to 95% by weight.

Other vinyl monomers that can be used in the vinyl monomer composition include, for example, unsaturated carboxylic acids such as maleic acid, styrene, vinyl toluene, and the like.

Furthermore, in combination with the above-mentioned acrylic pressure-sensitive adhesive, a tackifier such as ester gum, rosin resin, coumaron resin, phenol resin, polyterpene resin, etc. can also be used.

The acrylic pressure-sensitive adhesive can be used after being crosslinked if necessary, and examples of the crosslinking system include isocyanate, chelate, epoxy, melamine, and the like.

The thickness of the adhesive layer varies depending on the application, but is 15 to 60 μm.
A range of m is preferred.

A marking film is generally manufactured by applying an adhesive onto a release paper, heating and drying it, and then transferring it to a base film.

The marking film obtained by combining the above-mentioned base material and adhesive is cut into characters, figures, etc. in the desired size as necessary, and is pasted on the desired adherend for decoration, display, etc.
Used for advertising, etc.

(Example) Examples will be described below to further explain the plasticizer-resistant marking film.

Example 1 (base material dioctyl phthalate (hereinafter referred to as DOP)
It is abbreviated as. ) Immersion test) Immersion conditions: dicyclohexylmethane diisocyanate formed by casting method: polyhexamethylene carbonate diol (molecular weight 1000): 1, 4-butylene glycol: isophorone diamine = 4:1:1:1
A 50 μm thick aliphatic isocyanate-based polyurethane film consisting of (molar ratio) was cut into a size of 50 ss x 25 cm, and the dimensional change was measured after immersing it in DOP for 70 hours at room temperature.

The result was 50 m x 25 m, and the swelling rate was 0%.

Comparative Example 1 A vinyl chloride film was produced by casting with the following formulation to a thickness of 50 μm.

Vinyl chloride resin 100 parts ("Zeon 121" manufactured by Nippon Zeon Co., Ltd.) Polyester plasticizer 30 parts ("Polycizer W-305ELSJ" manufactured by Dainippon Ink Chemical Co., Ltd.) Stearic acid B a 0.5 part Stearic acid Z n 0.5 part This vinyl chloride film was tested under the same conditions as in Example 1.The results were 70 sheets x 35 m5, and the swelling rate was 4.
It was 0%.

Example 2 (1) Production of marking film Substrate Material: The same aliphatic isocyanate-based urethane film as in Example 1 formed by casting, thickness 501 parts m.
.

Adhesive Nibutyl acrylate: Acrylic acid: Vinyl acetate monomers are copolymerized at 75:5:20 (7) ml 1% to 100 parts of an acrylic polymer, and an isocyanate crosslinking agent ("Burnock D-750J: Dainippon Ink Chemical Co., Ltd. Acrylic adhesive containing 1 part (manufactured by).

The above-mentioned pressure-sensitive adhesive was applied onto release paper so that the thickness after drying was 30 μm, and dried at 80° C. for 90 seconds. Thereafter, a marking film was prepared by transferring it to the above-mentioned base material.

(2) Evaluation of marking film The marking film obtained in (1) was evaluated by the following method. The results are shown in Table 1.

(a) A marking film with an adhesive strength of 25 x 100 is coated with a plasticizer (D
2 kg of OP) on a vinyl chloride sheet containing 60 PHR.
It was crimped using a rubber roller. This is 70°C x 95
An accelerated test was conducted under conditions of %RH high temperature and high humidity, and changes in adhesive strength over time were measured.

The measurement conditions were in accordance with JIS z0237. Samples under the above conditions were taken out and heated at 23°C x 65% RH for 1 hour.
After standing for a period of time, the adhesive force was measured when it was peeled off at a speed of 300 m/min.

(b) Observation of marking film surface condition 25mX
50- marking film, plasticizer (DOP) 6
A vinyl chloride sheet containing 0 PI (R) was pressed using a 2 kg rubber roller. This was heated at 70°C x 95%RH.
A plasticizer migration acceleration test was conducted under high temperature and high humidity conditions, and the surface condition of the marking film was observed and visually judged according to the following criteria.

× Marking film base material swells and wrinkles occur on the entire base material Δ Blistering occurs on the marking film base material ○ No change from the initial stage of marking film application Comparative Example 2 Base material: Same vinyl chloride film as Comparative Example 1, thickness 5
0μm.

A marking film was produced in the same manner as in Example 2 except that the above base material was used.

This marking film was evaluated in the same manner as in Example 2, and the results are shown in Table 1.

Comparative Example 3 Adhesive Nibutyl Acrylate: Acrylic Polymer 10 copolymerized with each monomer of acrylic acid at a ratio of 95:5 by weight
0 parts, an isocyanate-based crosslinking agent ("Burnock D-7")
50J: An acrylic adhesive containing one part of Dainippon Ink Chemical Co., Ltd.).

A marking film was produced in the same manner as in Example 2, except that the above adhesive was used.

This marking film was evaluated in the same manner as in Example 2, and the results are shown in Table 1.

Comparative Example 4 Base material: Vinyl chloride film similar to Comparative Example 1, thickness 5
0μm.

Adhesive: Same as Comparative Example 3.

A marking film was produced in the same manner as in Example 2, except that the above base material and adhesive were used.

This marking film was evaluated in the same manner as in Example 2, and the results are shown in Table 1.

Example 3 Base material: Dicyclohexylmethane diisocyanate molded with T-die: Polybutylene adibate (molecular weight 200
0): 1.4-butylene glycol = 5:l:
An 80 μm thick aliphatic isocyanate-based polyurethane film consisting of 4 (molar ratio).

A marking film was produced in the same manner as in Example 2 except that the above base material was used.

This marking film was evaluated in the same manner as in Example 2, and the results are shown in Table 1.

Example 4 Base material: A 100 μm thick aliphatic isocyanate-based polyurethane film molded using a T-die and having the same composition as Example 3.

A marking film was produced in the same manner as in Example 2 except that the above base material was used.

This marking film was evaluated in the same manner as in Example 2, and the results are shown in Table 1.

Example 5 Base material: Aromatic isocyanate diphenylmethane diisocyanate containing 3 parts of carbon blank molded by casting: Polybutylene adipate (molecular weight 2000): 1.4 butylene glycol = 4:
A black aromatic isocyanate-based polyurethane film with a thickness of 50 μm, with a molar ratio of 1:3.

A marking film was produced in the same manner as in Example 2 except that the above base material was used.

This marking film was evaluated in the same manner as in Example 2, and the results are shown in Table 1.

Table 1 (Effects of the Invention) The plasticizer-resistant marking film of the present invention is a combination of a base material that does not swell due to plasticizer migration and an adhesive that exhibits little decrease in adhesive strength due to plasticizer migration.
Even if the plasticizer migrates from the adherend, the decrease in adhesive strength is small, and the marking film base material is not swollen by the plasticizer, and phenomena such as wrinkles and blisters do not occur.

Therefore, the marking film of the present invention can be used for tents, truck sails, internally illuminated signboards, soft vinyl chloride films containing highly migratable low molecular weight plasticizers, vinyl chloride molded products, plastic products, etc. Useful as a marking film.

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Claims (1)

[Claims] 1. An adhesive containing (a) a base material made of a film containing polyurethane, and (b) an acrylic adhesive made of a vinyl monomer composition containing an acrylic vinyl monomer and vinyl acetate. A marking film having a layer. 2. The marking film according to claim 1, wherein the polyurethane contains a non-yellowing polyurethane made of an aliphatic isocyanate. 3. The thickness of the film containing polyurethane is 20 to 2
2. The marking film according to claim 1, having a thickness in the range of 00 μm. 4. The marking film according to claim 1, wherein the vinyl monomer composition contains vinyl acetate in a range of 5 to 50% by weight.