JP3517341B2 - PSA composition for surface protective PSA sheet - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive composition for a surface-protective pressure-sensitive adhesive sheet, which has excellent low-temperature adhesiveness and high-speed peelability of a coating film.

[0002]

2. Description of the Related Art Conventionally, as a method of protecting the top coating surface of the vehicle body of a finished coating vehicle, there is a method of applying paraffin wax thinly on the coating surface. However, this method has problems that the protective function is not sufficient, that it takes time to remove the paraffin wax, and that the waste liquid generated during the removal leads to environmental pollution.

In addition, JP-A-6-73352 and JP-A-9-
A method of directly attaching a surface protective pressure-sensitive adhesive sheet to the coated surface shown in 3420 etc. is also known, but these pressure-sensitive adhesive sheets are particularly useful for difficult-to-adhere coating films excellent in water repellency and stain resistance. Adhesion at low temperature is poor, and it has a problem that it peels off during transportation in winter.

On the other hand, a surface protective pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing a hydrogenated product of a random copolymer of styrene and a diene-based hydrocarbon as a main component is proposed as a coating-film protective pressure-sensitive adhesive sheet having good low-temperature properties. (Japanese Patent Laid-Open No. 8-12
956). Further, there has been proposed a surface protective film of a coating film obtained by coating a support with an adhesive containing at least one of polyisobutylene, butyl rubber and polybutene as a main component (JP-A-8-143829). However, although it does not peel off during transportation of the vehicle, when peeling off the protective sheet after transportation, the peeling force during high-speed peeling becomes heavy, so the peeling workability is poor, and it sticks to the coating film surface due to the effect of the tackifying resin. There is a problem that traces remain.

[0005]

DISCLOSURE OF THE INVENTION The present invention has excellent water repellency, stain resistance, and adhesion to a coating having poor adhesion, particularly at low temperature, and when peeled, stains the adherend surface. An object of the present invention is to provide a pressure-sensitive adhesive for a low-temperature surface-protective pressure-sensitive adhesive sheet that can be easily peeled off at high speed without leaving a sticking mark.

[0006]

According to the present invention, 100 parts by weight of a blend comprising 50 to 100% by weight of polyisobutylene and / or butyl rubber and 50 to 0% by weight of polybutene is hydrogenated as a rosin-based tackifying resin. The present invention provides a pressure-sensitive adhesive composition for a coating film-protecting pressure-sensitive adhesive sheet on a vehicle body surface, characterized in that 5 to 30 parts by weight of the rosin ester resin is added.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In a pressure-sensitive adhesive composition for a surface-protective pressure-sensitive adhesive sheet of the present invention, polyisobutylene and / or butyl rubber 50 to 100% by weight and polybutene 50 to 50% by weight are used.
The above problems could be improved by adding 5 to 30 parts by weight of a rosin-based tackifying resin to 100 parts by weight of a blend consisting of 0% by weight.

In the pressure-sensitive adhesive composition of the present invention, when the polybutene content of the blend consisting of polyisobutylene and / or butyl rubber and polybutene exceeds 50% by weight, the peeling force at the time of high-speed peeling becomes heavy and the peeling work is performed. The performance may be poor, or the weather resistance may be poor.

Polyisobutylene and / or used in the present invention
Alternatively, the butyl rubber preferably has a viscosity average molecular weight of 400,000 to 1,500,000. When the viscosity average molecular weight is less than 400,000, the peeling force during high-speed peeling becomes heavy and the peeling workability deteriorates. If it exceeds 1.5 million, the low-temperature adhesiveness to the difficult-to-adhere coating film becomes poor.

The polybutene used in the present invention preferably has a number average molecular weight of 400 to 3,000. When the number average molecular weight is less than 400, the peeling force during high-speed peeling becomes heavy and the peeling workability deteriorates. When it exceeds 3,000, the low-temperature adhesiveness to the coating film having poor adhesion becomes poor.

In the pressure-sensitive adhesive composition of the present invention, when the amount of the rosin-based tackifying resin added to 100 parts by weight of the blend of polyisobutylene and / or butyl rubber and polybutene is less than 5 parts by weight, a film having poor adhesiveness is formed. Low temperature adhesiveness to. When the amount of the rosin-based tackifying resin added exceeds 30 parts by weight, the low temperature adhesiveness and weather resistance are deteriorated and the adherend surface is contaminated.

The rosin-based tackifying resin used in the present invention is preferably a rosin ester-based resin, and more preferably a hydrogenated rosin ester-based resin from the viewpoint of weather resistance.

The surface protective pressure-sensitive adhesive sheet using the pressure-sensitive adhesive composition of the present invention has a wettability (based on JIS K6760) of 3
Adhesive strength (180 ° peeling force, peeling speed 0.3 m /
Min., JIS Z0237) 0.4N / 10mm or more, high-speed peeling force (180 ° peeling force, 23 ° C atmosphere)
Pretreatment 70 ° C x 24 hours, peeling speed 40m / min, JIS
(Based on Z0237) is less than 2N / 10 mm. Adhesive strength at -20 ℃ is 0.4N / 1
When the thickness is less than 0 mm, the low temperature adhesiveness is deteriorated and peeling easily occurs at low temperature transportation. High-speed peeling force of 2N at 23 ℃
When it is / 10 mm or more, the peeling workability becomes poor.

The pressure-sensitive adhesive composition of the present invention may contain various additives, if necessary, within a range not impairing the object of the present invention. That is, oils, paraffin wax, softeners such as epoxy plasticizers and polyester plasticizers; pigments such as titanium oxide; fillers such as talc and calcium carbonate; stearic acid, stearamide, calcium stearate, barium stearate, Lubricants such as zinc stearate; phenol-based, phosphite-based,
Antioxidants such as thioethers; UV absorbers such as benzotriazoles, hindered amines and benzoates; inorganic hollow particles such as glass balloons and silica balloons; polymer microspheres such as acrylic and high molecular weight polyolefin powders; A silicone-based or long-chain alkyl-based releasability-imparting agent or the like can be appropriately added.

The base material layer of the coating film protective sheet using the pressure-sensitive adhesive composition of the present invention is preferably a film having a thickness of 6 to 1,000 μm. The base material composition is polyester, nylon, polyvinyl chloride, Polyethylene, polypropylene, copolymer of ethylene and propylene, copolymer of ethylene, propylene and diene, copolymer of ethylene and butene-1, copolymer of ethylene and α-olefin, copolymer of ethylene and vinyl acetate A copolymer of ethylene and (meth) acrylic acid, a copolymer of ethylene and methyl (meth) acrylate, a copolymer of ethylene and ethyl (meth) acrylate, and a metal ion bond between ethylene-based polymers. Ionomer resin, olefin crystal / diene hydrocarbon / olefin crystal block copolymer (including hydrogenated products) Styrene-diene hydrocarbon-
One or more resins such as olefin crystal block copolymers (including hydrogenated products) and styrene / diene hydrocarbon random copolymers (including hydrogenated products), blends, or alloys; Pigments such as titanium oxide; fillers such as talc and calcium carbonate; lubricants such as stearic acid, stearamide, calcium stearate, barium stearate and zinc stearate; antioxidants such as phenols, phosphites, thioethers, etc. UV absorbers such as benzotriazole-based, hindered amine-based, benzoate-based; inorganic hollow particles such as glass balloons and silica balloons; high-molecular weight microspheres such as high-molecular-weight polyolefin powder; silicone-based, long-chain alkyl-based release It is possible to use a material to which a property-imparting agent or the like is appropriately added.

The pressure-sensitive adhesive composition of the present invention has a content of 1 to 200 μm.
It can be used by a known method such as spread coating, hot melt extrusion coating, or co-extrusion with a base layer resin on a supporting substrate so that the thickness is preferably 5 to 50 μm.

[0017]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

The components used are as follows.

(1) Polyisobutylene (hereinafter "PIB")
PIB-1: Vistanex MML80 (polyisobutylene manufactured by Exxon Co., viscosity average molecular weight 990,000) (2) Butyl rubber (hereinafter abbreviated as “IIR”) IIR-1: JSR butyl 268 (manufactured by Japan Synthetic Rubber Co., Ltd.) Butyl rubber, viscosity average molecular weight 450,000) (3) Polybutene (abbreviated as "PB" hereinafter) PB-1: Idemitsu Polybutene 300R (Polybutene by Idemitsu Petrochemical Co., Ltd., number average molecular weight 1,500) (4) Tackifying resin ( AR-1: Pine Crystal KE-311 (hydrogenated rosin ester resin manufactured by Arakawa Chemical Industry Co., Ltd.) AR-2: Clearon P-85 (hydrogenated terpene resin manufactured by Yasuhara Chemical Co., Ltd.) AR- 3: Alcon P-100 (Arakawa Chemical Industry's alicyclic saturated hydrocarbon resin) AR-4: YS Polystar T1 15 (Terpene phenolic resin manufactured by Yasuhara Chemical Co., Ltd.) (5) Additive (abbreviated as "AD" hereinafter) AD-1: Tinuvin 622LD (Hindered amine UV stabilizer manufactured by Ciba Geigy) AD-2: Irganox 565 (Ciba Geigy) (Made by hindered phenolic antioxidant)

Examples 1 to 6 and Comparative Examples 1 to 8 A pressure-sensitive adhesive composition having the composition shown in Table 1 was dissolved in a toluene solvent on one side of a white polyethylene film having a thickness of 60 μm. It was spread coating.

[0021]

[Table 1]

The surface protective pressure-sensitive adhesive sheets obtained in Examples 1 to 6 and Comparative Examples 1 to 8 were attached to an acrylic hard-to-adhere coating film, and the low-temperature adhesiveness to the adherend, high-speed peelability and weather resistance were obtained. Was tested. The weather resistance was evaluated by a weatherometer for removability after carbon arc irradiation, contamination of the adhered surface after peeling, and presence or absence of sticking marks.

Difficult-to-adhesive coating film: wettability (JIS K676
0) Difficult-to-adhesive acrylic coating less than 30 dyn / cm (containing silicone) Carbon arc irradiation: Carbon arc 300 hours irradiation by sunshine weatherometer (60 hours rainfall) Low temperature adhesion: 180 in -20 ° C atmosphere ° Peeling force (adherent; hardly adhesive acrylic coating, peeling speed; 0.3m /
Min., According to JIS Z0237), evaluation result; good 0.4N / 10mm or more, bad 0.4N / 10mm or less (paste the surface protective adhesive sheet sample on a completed car coated with a non-adhesive acrylic paint,- 1 hour / hour in 20 ° C atmosphere
Run test at a speed of 00 km and set based on the result of evaluation of the presence or absence of peeling) High speed peelability: 180 ° peeling force in an atmosphere of 23 ° C (adherend: difficult-to-adhesive acrylic coating, peeling speed: 40 m / Minutes,
(Based on JIS Z0237) was measured and evaluated;
Less than 2N / 10mm, bad 2N / 10mm or more (set based on the result of pasting the surface protection adhesive sheet sample on the completed car coated with the non-adhesive acrylic paint and evaluating the peeling workability) Removability: 23 after carbon arc irradiation Peeling by hand in ℃ atmosphere, evaluation result; Good Easy peeling, bad Difficulty peeling Contamination / sticking mark on adherend: Visual evaluation of adherend after high-speed peelability evaluation and re-peeling evaluation

The test results are shown in Table 2.

[0025]

[Table 2]

As is clear from the results of Examples 1 to 6 in Table 2, the low-temperature surface-protective pressure-sensitive adhesive sheet using the pressure-sensitive adhesive composition of the present invention has good low-temperature adhesiveness to a difficult-to-adhere coating film, High speed peeling force is light. Further, peeling after the carbon arc irradiation was easy, and the adherend surface was not contaminated and no trace of sticking was left.

On the other hand, as in Comparative Example 1, when polyisobutylene alone is contained in the pressure-sensitive adhesive formulation and no tackifying resin is contained, the low-temperature adhesiveness to the poorly-adhesive coating film becomes poor.

Even in the case where only the blend of polyisobutylene and polybutene is contained in the pressure-sensitive adhesive composition and no tackifying resin is contained as in Comparative Example 2, the low-temperature adhesiveness to the poorly-adhesive coating film is deteriorated.

As in Comparative Example 3, when the rosin-based tackifying resin was more than 30 parts by weight with respect to 100 parts by weight of the blend of polyisobutylene and polybutene during the formulation of the adhesive, low temperature adhesiveness, high speed peelability, The weather resistance will deteriorate and the adherend will be contaminated.

As in Comparative Example 4, when the proportion of polybutene in the blended product in the composition of the pressure-sensitive adhesive exceeds 50% by weight, the high speed peelability and the weather resistance are deteriorated.

As in Comparative Example 5, when polyisobutylene was not included in the pressure-sensitive adhesive composition and only the tackifying resin was added to polybutene, the high-speed peelability and weather resistance were deteriorated, and the adherend surface was To pollute.

As in Comparative Example 6, when a terpene resin is used instead of a rosin resin as the tackifying resin in the pressure-sensitive adhesive composition, the low-temperature adhesiveness to the coating film having poor adhesion deteriorates.

As in Comparative Example 7, when a petroleum resin is used instead of a rosin resin as the tackifying resin in the pressure-sensitive adhesive formulation, the low-temperature adhesiveness to the poorly-adhesive coating film deteriorates.

As in Comparative Example 8, when a terpene phenol resin was used instead of a rosin resin as the tackifying resin in the adhesive formulation, the weather resistance was poor and the adherend surface was contaminated. Or

[0035]

EFFECT OF THE INVENTION The pressure-sensitive adhesive composition of the present invention has a low peeling force at high-speed peeling, but has a certain range of polybutene and polybutylene and / or butyl rubber having poor adhesion to a difficult-to-adhere coating film. Provided is a surface-protective pressure-sensitive adhesive sheet having a high-speed peeling force which is light by adding a rosin-based tackifying resin and which has improved low-temperature adhesiveness to a difficult-to-adhere coating film.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kinnosuke Hino 2-3-3 Sekiguchi, Bunkyo-ku, Tokyo Nichiban Co., Ltd. (56) Reference JP-A-54-96539 (JP, A) Special features Kai 60-123574 (JP, A) JP-A-8-143829 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09J 1/00-201/10

Claims (2)

(57) [Claims] 1. A hydrogenated rosin ester resin 5 as a rosin-based tackifying resin is added to 100 parts by weight of a blend comprising 50 to 100% by weight of polyisobutylene and / or butyl rubber and 50 to 0% by weight of polybutene.
A pressure-sensitive adhesive composition for a coating film-protecting pressure-sensitive adhesive sheet on a vehicle body surface, comprising 30 parts by weight. 2. Adhesive strength (180 ° peel force, peeling speed 0.3 m / min) in an atmosphere of −20 ° C. is 0.4 N / 10 mm with respect to a coating having poor wettability of less than 30 dyn / cm. Above 2
High speed peeling force (180 ° peeling force, pretreatment 70 ° C x 24 hours, peeling speed 40m / min) in 2 ℃ / 10mm in 3 ℃ atmosphere
The composition of claim 1, which is less than.