JP3041733B2 - Manufacturing method of pressure-sensitive adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape having a high adhesive strength (shear adhesive strength and peel adhesive strength) comprising a pressure-sensitive adhesive layer laminated on a substrate having both flexibility and high tensile strength. The present invention relates to a method for producing a pressure-sensitive adhesive in the form of a sheet.

[0002]

2. Description of the Related Art Conventionally, several methods for obtaining a tape-shaped or sheet-shaped pressure-sensitive adhesive having a relatively high adhesive strength have been known. For example, as a method of obtaining a pressure-sensitive adhesive having a relatively high adhesive strength, a method of thickening a pressure-sensitive adhesive layer is known. As long as the pressure-sensitive adhesive layer is formed by using, there is a limit in the thickness, and thus there is also a limit in the adhesive strength.

When a thick foam is used as the base material, the adhesiveness of the pressure-sensitive adhesive becomes relatively good. However, in the case of urethane foam or polyethylene foam, which is the most common, a relatively high shear adhesive strength is obtained. When trying to obtain, the peel adhesive strength is not sufficient, and when having a relatively high peel adhesive strength, there is a limit to the shear adhesive strength as a pressure-sensitive adhesive,
There is a problem that it is not easy to combine a relatively high peel adhesive strength and a relatively high shear adhesive strength, and satisfactory properties are not obtained.

In order to solve such a problem, a pressure-sensitive adhesive film containing a specific kind of air bubbles at a specific ratio has been produced, and a pressure-sensitive adhesive having both flexibility and relatively high adhesive strength has been obtained. (JP-A-58-125776). However, this pressure-sensitive adhesive is a special material containing specific types of air bubbles at a specific ratio, and is different from the usual method, that is, after foaming a composition that becomes a pressure-sensitive adhesive state when polymerized, It must be put on a material and polymerized on site before the foam of the foamed material disappears to have a pressure-sensitive adhesive property, it is said that it will be quite special in morphology and manufacturing method There are drawbacks.

[0005] A pressure-sensitive adhesive tape containing glass microbubbles instead of the air bubbles has been studied (Japanese Patent Application Laid-Open Nos. 53-141346 and 62-34).
No. 976), the fact is that bubbles are easily broken at the time of mixing, and care is taken in handling.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a tape-shaped or sheet-shaped pressure-sensitive adhesive having flexibility and relatively high adhesive strength.

[0007]

The above object is achieved by the present invention described below. 1) A tape-shaped or sheet-shaped pressure-sensitive adhesive obtained by laminating a pressure-sensitive adhesive layer and a substrate obtained by crosslinking and curing a composition mainly composed of a rubber-based organic polymer that is liquid at room temperature. A method for producing a pressure-sensitive adhesive, comprising: laminating a base material layer on a pressure-sensitive adhesive layer; and laminating the base layer sides.

2) The composition comprising the rubber-based organic polymer as described in 1) above as a main component has (A) a hydroxyl group or a hydrolyzable group bonded to a silicon atom, and is crosslinked by forming a siloxane bond. The tape-shaped or sheet-shaped curable composition according to claim 1, wherein the curable composition is a rubber-based organic polymer which is liquid at room temperature and has at least one silicon-containing group in a molecule, and (B) a curing catalyst. Manufacturing method of pressure sensitive adhesive. 3) The composition comprising, as a main component, the rubber-based organic polymer described in 1) above, (A) silicon having a hydroxyl group or a hydrolyzable group bonded to a silicon atom, and capable of being crosslinked by forming a siloxane bond. The curable composition according to claim 1, which is a curable composition containing a rubber-based organic polymer which is liquid at room temperature having at least one containing group in a molecule and (B) a curing catalyst as a main component and a tackifier resin. Manufacturing method of sheet-shaped pressure-sensitive adhesive. In the present invention, a composition containing a rubber-based organic polymer that is liquid at room temperature (hereinafter, also referred to as a specific rubber-based organic polymer) as a main component is used.

[0009] As the name implies, the specific rubber-based organic polymer is required to be rubbery after curing or the like and to have flexibility. The term “flexible” as used in the present specification means that the elasticity at room temperature is 1 × 10 ⁸ d, although it can be bent with very little finger force at room temperature.
yne / cm ² or less, preferably 5 × 10 ⁷ dyne /
cm ² or less.

From this viewpoint, the specific rubber-based organic polymer has properties such as being liquid at ordinary temperature, ie, having fluidity at about 5 to 35 ° C., and being easily kneaded at room temperature without a plasticizer, If necessary, a solvent or the like must be used in combination to be easily formed into a tape shape or a sheet shape. Further, since the base material is formed after being formed into a tape shape or a sheet shape, it is necessary to have at least one reactive group in the molecule. Further, it must be a rubber-based polymer.

Examples of such a specific rubber-based organic polymer include a rubber-based organic polymer which has at least one reactive silicon group in a molecule and is liquid at room temperature (hereinafter referred to as a rubber-based organic polymer (A)). ), And has at least one hydroxyl group, isocyanate group, glycidyl group, acryloyl group, methacryloyl group, vinyl group, allyl group, amino group, amide group, carboxyl group, mercapto group and the like as a reactive group. An organic polymer which is liquid at room temperature can be mentioned, but a rubber organic polymer (A) is preferable from the viewpoint of the flexibility of the substrate after curing.

The main chain of the specific rubber-based organic polymer is not particularly limited as long as the cured product is an organic polymer capable of forming a rubber-like material. The main chain is essentially of the general formula: -RO-
(Where R is a divalent organic group) a polyether having a repeating unit represented by the following formula: Radical polymerization of an acrylate such as 2-ethylhexyl acrylate or butyl acrylate as described in JP-A-59-168014 Japanese Patent Application No. 62-327938, polyacrylates obtained by the above method, and acrylate copolymers of acrylates such as 2-ethylhexyl acrylate and butyl acrylate with vinyl acetate, acrylonitrile, methyl methacrylate and styrene. Saturated hydrocarbon polymers such as isobutylene polymer and hydrogenated polydiene polymer as described in the specification and Japanese Patent Application No. 62-330890: polymerization of cyclic ethers such as propylene oxide, ethylene oxide, and tetrahydrofuran. Was obtained Carbon number 1 in Rieteru based polymer
And a vinyl polymer-modified polyether-based polymer obtained by polymerizing vinyl monomers such as acrylic acid ester and methacrylic acid ester of alcohol No. 12, vinyl acetate, acrylonitrile, and styrene.

Of these, a polymer represented by the general formula: -R
The repeating unit represented by -O- is not less than 50% (% by weight, the same applies hereinafter), preferably not less than 70%, more preferably not less than 9%.
A polyether polymer containing 0% or more is preferable, and a polypropylene oxide polymer is particularly preferable. Further, the reactive silicon group contained in the rubber-based organic polymer (A) is a well-known group and has a feature that it can be crosslinked at room temperature.

An example of such a reactive silicon group is a group represented by the general formula (1) shown in [Chemical Formula 1].

[0015]

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(In the formula, X is a hydroxyl group or a hydrolyzable group, and when two or more are present, they may be the same or different. R ¹ is 1 to 20 carbon atoms.)
A monovalent hydrocarbon group or (R ′) ₃ —SiO— (R ′ is a monovalent hydrocarbon group having 1 to 20 carbon atoms,
R's may be the same or different), and when two or more R ¹ are present, they may be the same or different . a is 0, 1, 2 or 3, b is 0, 1 or 2, provided that 1 ≦ a + mb, and b in the m linking groups represented by the formulas need not be the same, and m is 0 or 1 to 19) Preferred reactive silicon groups are groups represented by the general formula (2) shown in [Chemical Formula 3].

[0017]

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[0018]

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Wherein X is the same as above, and R ² is a carbon group 1
To 18 monovalent hydrocarbon groups, n is 1, 2 or 3) A curing catalyst (B) is a component used in the specific rubber-based organic polymer and copolymer constituting the base material composition. . The curing catalyst (B) acts on the rubber-based organic polymer used in the present invention to crosslink and cure, thereby producing a stable base composition. The curing catalyst used together with the rubber-based organic polymer (A) is not particularly limited, and a commonly used silanol condensation catalyst is used.

Specific examples of such a curing catalyst (B) include, for example, titanates, tin carboxylate salts,
Organic zirconium compounds, reactants of dibutyltin oxide with phthalates, chelate compounds, lead octylate, amine compounds, acidic phosphates, saturated or unsaturated polyvalent carboxylic acids or anhydrides, amine compounds and acidic phosphoric acid Examples thereof include a reaction product with an ester, a reaction product of an amine compound with a saturated or unsaturated polycarboxylic acid or an anhydride thereof, and other known silanol catalysts such as an acidic catalyst and a basic catalyst.

The amount of the curing catalyst (B) used is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the rubber organic polymer (A). The amount is 0.
If it is less than 1 part by weight, the catalytic effect is not sufficient, and if it exceeds 10 parts by weight, the curing is too fast, and the workability of coating on the support deteriorates. As a component that can be used other than the specific rubber-based organic polymer constituting the composition for a base material, there is a tackifier resin used for adjusting the flexibility of the base material and increasing the strength. There is no particular limitation on the tackifier resin, and any commonly used tackifier resin can be used.

Specific examples of such tackifier resins include, for example, phenolic resins, modified phenolic resins, terpene-phenolic resins, petroleum resins, rosin ester resins, low molecular weight polystyrene resins, terpene resins and the like. These may be used alone or as a mixture of two or more. Among these, phenol resin-based and phenol-containing resin-based resins are particularly preferred because they easily exhibit flexibility, high elongation and high strength.

When the tackifier resin is used together with the rubber organic polymer (A), the amount of the rubber organic polymer (A)
0 to 140 parts by weight, more preferably 5 to 8 parts by weight, per 100 parts by weight
0 parts by weight is preferred. If the amount exceeds 140 parts by weight, a high elastic modulus is obtained, and a rubber-like property cannot be sufficiently obtained. As other components to be used, a filler can be used for adjusting the physical properties of the base material and the viscosity of the base material composition used for cost reduction, and a solvent can be used.

Also, an antioxidant, an ultraviolet absorber, a pigment,
Surfactants and the like are used according to the respective purposes, but are not limited thereto. In the present invention, in mixing the rubber-based organic polymer with other components, a Banbury mixer, a kneader, a roll, a mixer such as a planetary mixer may be used, and when a tackifying resin is used, 1 ~ 100μ
By pulverizing to a fine powder state of about m, mixing becomes easy. The fine powder of the tackifier resin does not necessarily have to be in a homogeneously dissolved state before coating,
It may be present in the rubber-based organic polymer as small particles in a non-uniformly dispersed state.

The production of a cured sheet from the curable composition prepared as described above is usually achieved by applying the composition to a silicon release paper or the like, drying and curing. The coating method is not particularly limited, and the curable composition may be applied using a usual coater. After coating,
The drying / curing step is performed. The drying and curing conditions are from room temperature to 150 ° C. for about 0.5 to 60 minutes.

The tape-shaped or sheet-shaped pressure-sensitive adhesive of the present invention comprises a cured sheet obtained as described above as a base material, on which a pressure-sensitive adhesive layer is laminated. The state of the pressure-sensitive adhesive layer when the substrate is laminated on the pressure-sensitive adhesive layer may be either wet or dry, but when a solvent-type pressure-sensitive adhesive is used, the drying of the solvent is easy. In consideration of the above, it is preferable to stack the layers in a dry state in advance.

The state of the base material layer when the base material is laminated on the pressure-sensitive adhesive layer may be uncured, semi-cured, or almost completely cured. Considering the size of the bonding strength of the superposed surface, it is desirable that the reactive group remains even a little, while the completely uncured state is difficult to handle during subsequent superposition,
A semi-cured to almost completely cured state is preferred. The curing reaction of the substrate layer is completed after the surfaces of the substrate layers are overlapped, and the substrate layer becomes an integral substrate layer.

The pressure-sensitive adhesive used in the present invention is not particularly limited. For example, a solvent-type, emulsion-type or solvent-free acrylate copolymer-based pressure-sensitive adhesive, or a tackifier resin to natural rubber or synthetic rubber. Solvent-type or hot-melt type adhesives obtained by blending, and other pressure-sensitive adhesives are used. The thickness of the pressure-sensitive adhesive layer thus formed is not particularly limited, but is usually about 5 μm to 1 mm, preferably 25 to 200 μm.

[0029]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. Example 1 A pressure-sensitive adhesive layer was formed as follows. That is, a commercially available solvent-type acrylic pressure-sensitive adhesive (manufactured by Yushi Co., Ltd.) is dried on a silicone release paper (EK-130R, manufactured by Souken Kako Co., Ltd.) using a doctor blade to a thickness of 100.
μm, and dried at 60 ° C. for 3 minutes.
Cured at 0 ° C for 2 minutes.

On the other hand, 100 parts by weight of a polymer composed of propylene oxide having an average molecular weight of 9200 and having an average of 1.0 dimethoxysilyl groups per molecule: --Si (CH ₃ ) (OCH ₃ ) ₂ (hereinafter referred to as propylene oxide-based) Polymer (A)), straight novolak phenolic resin (trade name: PR-, manufactured by Sumitomo Bakelite Co., Ltd.)
50731), 1 part by weight of an antioxidant (Nocrack NS-6), and an ultraviolet absorber (Tinuvin 32)
7) 1 part by weight, 7.5 parts by weight of Shirasu balloon, 5.6 parts by weight of an acid / base silanol condensation catalyst, and 0.75 parts by weight of carbon black were added and uniformly mixed. This was applied on a silicon release paper (EK-130R) using a doctor blade so that the thickness became 500 μm, and heat-treated at 120 ° C. for 10 minutes to obtain a base material layer. The gel content of this base material layer was 34%.

Two pieces of the above-mentioned acrylic pressure-sensitive adhesive layer were superposed on one side of the base material layer, and the base material layers were superposed on each other to form an acrylic pressure-sensitive adhesive layer on both sides. The laminated adhesive tape was obtained. Example 2 An acrylic pressure-sensitive adhesive layer was applied, dried and cured in the same manner as in Example 1.

Thereafter, the base composition used in Example 1 was applied from above the acrylic pressure-sensitive adhesive layer using a wide doctor blade so that the thickness of the base layer was 500 μm. At 120 ° C. for 10 minutes. The gel content of this substrate layer was isolated and measured to be 32%. The base material layer side of this laminate was overlaid to obtain an adhesive tape having an acrylic pressure-sensitive adhesive layer laminated on both sides. Comparative Example 1 An acrylic pressure-sensitive adhesive layer and a substrate layer were obtained in the same manner as in Example 1, except that the thickness of the substrate layer was changed to 1000 μm.

An acrylic pressure-sensitive adhesive layer was superposed on both sides of the substrate layer to obtain a double-sided adhesive tape. Comparative Example 2 A substrate layer was laminated on the acrylic pressure-sensitive adhesive layer in the same manner as in Example 2, except that the coating was performed so that the thickness of the substrate layer was 1000 μm.

The commercially available solvent-type acrylic pressure-sensitive adhesive used in Example 1 was further coated on the substrate layer surface with a paste thickness of 100 μm.
m and dried and cured under the same conditions as in Example 1 to obtain a double-sided adhesive tape. The adhesive properties of the obtained double-sided adhesive tape were measured by the following method. Table 1 shows the results
Shown in

[0035]

[Table 1]

[180 ° Peeling Strength] A 2.5 cm wide double-sided adhesive tape piece lined with a polyester film having a thickness of 50 μm was prepared and bonded to a coated steel sheet. After leaving it at room temperature for one day, it was
Under the atmosphere of 3 ° C. and 80 ° C., 50 mm / min.
The 80 ° peel strength was measured. [Shear bond strength] 2mm thick, 2.5cm wide, 8c long
An approximately 3.2 cm ² end of a soft PVC plate adhered with a steel plate of the same size as a painted steel plate of length m was bonded with a double-sided adhesive tape. After leaving this at room temperature for one day, the tensile shear adhesive strength was measured at 23 ° C. and 80 ° C. atmosphere at a tensile strength of 50 mm / min using an autograph manufactured by Shimadzu.

From Table 1, it can be seen that the product of the present invention has the same adhesive properties as the sequential laminating method of Comparative Example 1, and does not adversely affect the adhesive strength due to the residual solvent as in Comparative Example 2. Therefore, as a method for producing a tape-sheet-shaped pressure-sensitive adhesive obtained by laminating a pressure-sensitive adhesive layer and a substrate obtained by crosslinking and curing a composition mainly composed of a liquid rubber-based organic polymer at room temperature. It turns out to be useful.

[0038]

The pressure-sensitive adhesive obtained by the method of the present invention has an elastic modulus at room temperature of 1 × 10 ⁸ dyn / cm ² or less, particularly 5 × 10 ⁷ dyn / cm ² or less. Since it has flexibility, stable high peel adhesive strength and shear adhesive strength, and is easy to mix in color including black in appearance, and is relatively inexpensive, it can be used for automobile products (for example, side It can be suitably used for applications such as bonding of moldings, emblem moldings, weather strips, etc.), assembling and fixing electric appliances, room furniture, display boards, building materials, and the like, and its industrial value is very high.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C09J 7/02

Claims (3)

(57) [Claims] 1. A tape-shaped or sheet-shaped sensor comprising a substrate obtained by crosslinking and curing a composition mainly composed of a rubber-based organic polymer which is liquid at normal temperature and a pressure-sensitive adhesive layer laminated thereon. In producing a pressure-sensitive adhesive, a method for producing a pressure-sensitive adhesive, comprising: 1) laminating a base material layer on a pressure-sensitive adhesive layer; and 2) laminating the base layer sides together. 2. A composition comprising the rubber-based organic polymer according to claim 1 as a main component, comprising: (A) a hydroxyl group or a hydrolyzable group bonded to a silicon atom, and crosslinking by forming a siloxane bond. The tape-shaped or sheet-shaped curable composition according to claim 1, wherein the curable composition is a rubber-based organic polymer which is liquid at room temperature and has at least one silicon-containing group in a molecule, and (B) a curing catalyst. Manufacturing method of pressure sensitive adhesive. 3. A composition comprising the rubber-based organic polymer according to claim 1 as a main component, comprising: (A) a hydroxyl group or a hydrolyzable group bonded to a silicon atom, and crosslinking by forming a siloxane bond. The curable composition according to claim 1, wherein the curable composition contains a rubber-based organic polymer which is liquid at room temperature and has at least one silicon-containing group in the molecule, and (B) a curing catalyst, and a tackifier resin. A method for producing a tape-to-sheet pressure-sensitive adhesive.