JPH07126601A - Acrylic tacky agent - Google Patents

Abstract

PURPOSE:To obtain an acrylic tacky agent useful for a double-coated tacky tape, etc., having excellent initial tack, durability and weather resistance by blending an acrylic main agent with a specific curing agent in a specific ratio. CONSTITUTION:This acrylic tacky agent is obtained by mixing (A) 100 pts.wt. of a solid content of an acrylic main agent such as polymethyl acrylate with (B) 0.05-5 pts.wt. of a compound of formula I containing a tack imparting component group and two isocyanate groups as a curing agent. The compound of formula I is obtained by subjecting 2 mols of 2,4-tolylene diisocyanate and a xylene resin of formula II to addition reaction.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an acrylic pressure-sensitive adhesive, and more specifically, by using an addition reaction product of a tackifying resin having a functional group reactive with an isocyanate group and a polyisocyanate compound as a curing agent. The present invention relates to an acrylic pressure-sensitive adhesive capable of increasing the initial adhesive force and suppressing a decrease in adhesive strength over time (durability, weather resistance deterioration) under dry heat and wet heat.

[0002]

BACKGROUND OF THE INVENTION Acrylic pressure-sensitive adhesives conventionally used for one-sided or double-sided pressure-sensitive adhesive tapes, pressure-sensitive adhesive labels, etc. are, for example, acrylic-based pressure sensitive adhesives composed of a polymer based on 2-ethylhexyl acrylate. As a main agent, a diisocyanate compound such as 2,4-tolylene diisocyanate (TDI) or 4,4'-diphenylmethane diisocyanate (MDI) as a curing agent or a modified product thereof, for example, a TDI3 adduct of 1,1,1-trimethylolpropane The expression that is:

[Chemical 4] (Commercially available, "Coronate L" manufactured by Nippon Polyurethane Co., Ltd.) (hereinafter, abbreviated as TMP-3TDI compound)
In order to further increase the initial adhesion, a tackifying resin (for example, rosin, hydrogenated rosin, alkylphenol resin rosin, alkylphenol-modified xylene resin, terpene phenol resin, terpene resin, petroleum resin, coumarone-indene resin, etc.) is added. Has been done. However, although the initial adhesive strength is increased by using the tackifying resin as described above, since a large amount of tackifying resin is required,
As a result, it deteriorates due to heat and humidity, resulting in problems such as durability of adhesive strength and weather resistance.

[0003]

Therefore, the present inventors have
When the above-mentioned initial adhesive force was raised, and the acrylic adhesive having no problem in adhesive strength durability, weather resistance, etc. was studied earnestly, as a curing agent for the acrylic main agent,
If a small amount of an addition reaction product of a tackifying resin having a functional group reactive with an isocyanate group and a polyisocyanate compound, that is, a compound containing a tackifying component group and two isocyanate groups is added, the desired acrylic resin can be obtained. It was found that a pressure-sensitive adhesive can be obtained, and the present invention has been completed.

That is, according to the present invention, 0.05 to 5 parts of a compound containing a tackifying component group and two isocyanate groups as a curing agent is added to 100 parts (parts by weight, hereinafter the same) of the solid content of the acrylic main agent. The present invention provides an acrylic pressure-sensitive adhesive characterized in that

As the acrylic main agent in the present invention,
Those known in the art can be used without limitation,
For example, alkyl acrylate (methyl acrylate,
(Ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, cyclohexyl acrylate, etc.)
And at least one selected from the group of alkyl methacrylate (methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isooctyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate). As a base, other vinyl-based monomers (styrene, vinyltoluene, α-methylstyrene, vinyl acetate, etc.) and functional monomers (2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2
-Hydroxybutyl methacrylate, 2-hydroxypentyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxypentyl acrylate, methacrylic acid, acrylic acid, aminomethyl methacrylate, N-methylaminomethyl Methacrylate, N, N-dimethylaminoethyl methacrylate, aminomethyl acrylate, N-methylaminomethyl acrylate, N, N-dimethylaminoethyl acrylate, glycidyl methacrylate, glycidyl acrylate, methacrylamide, acrylamide, etc.) are added and solution polymerization is performed. The resulting polymer solution may be mentioned.

The compound containing a tackifying component group and two isocyanate groups (NCO) used as a curing agent in the present invention has a functional group (hydroxyl group, carboxyl group, glycidyl group, etc.) reactive with NCO. By specifically reacting the tackifying resin with which the polyisocyanate compound is added, for example, it can be produced by the following two modes.

[0007] The tackifying resin containing the 1 2 hydroxyl groups (OH)
(Xylene resin or rosin), for example of formula:

[Chemical 5] 2 mol of the OH-containing xylene resin (II) of 2 mol of diisocyanate compound (TDI, MDI, xylylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, etc.), for example, TDI By the addition reaction, the formula:

[Chemical 6] The compound (I) of is obtained. This compound (I) contains TD and a tackifying component group introduced from the xylene resin (II).
It is a novel compound of room temperature viscous liquid containing two NCOs introduced from I and forms part of the present invention.

( 2 ) The triisocyanate compound (such as triphenylmethane triisocyanate) is subjected to an addition reaction of one OH-containing tackifying resin with one NCO to give a tackifying component group and two NCO-containing compounds. Obtain the compound.

The amount of such a curing agent used is selected in the range of 0.05 to 5 parts, preferably 1.0 to 4.0 parts, based on 100 parts of the solid content of the acrylic main agent. If it is less than 0.05 part, the reactivity is lowered and the heat resistance and cohesive force are lowered, and if it is more than 5 parts, the tackiness is lowered.

The acrylic pressure-sensitive adhesive according to the present invention is composed of the above-mentioned predetermined ratio of the acrylic main agent and the curing agent, and is usually applied to release paper in a dry film thickness of 30 to 500 μ (roll coater, spray, etc.). Then, it is dried and cured at a temperature of 80 to 120 ° C., and then laminated with a tape support such as polyolefin (polyethylene, polypropylene), polybutadiene, polyethylene terephthalate or the like to obtain an adhesive tape. In adhesive applications, any adherend such as plastic, metal,
It can be attached to glass, paper, ceramic, etc.

[0011]

The pressure-sensitive adhesive of the present invention having the above constitution is used for one-sided or double-sided pressure-sensitive adhesive tapes, pressure-sensitive adhesive labels, etc.
Since it exhibits excellent initial adhesive strength as an adhesive and can suppress the decrease in adhesive strength over time under dry heat and wet heat, it can sufficiently cope with the durability and weather resistance required for practical use. It can be said to be a thing.

[0012]

EXAMPLES Next, production examples, examples and comparative examples will be given.
The present invention will be described more specifically. In addition, the manufacturing example shows the manufacturing method of the hardening | curing agent used by this invention.

Production Example 1 The two OH-containing xylene resins (II) (Mitsubishi Gas Chemical Co., Ltd.)
Nikonol K-100, 1020 g (1 mol) manufactured by Co., Ltd. was dissolved in 50% with toluene, and TDI 348 g (2 mol) and dibutyltin dilaurate 1.37 g were added thereto,
The mixture is heated at 60 ° C. for 24 hours to carry out an addition reaction to obtain the compound (I) as a viscous liquid at room temperature. Number average molecular weight (GPC method) 1
500-2000, viscosity 120 cps. The reaction product was identified by NMR. Below, such compounds
(I) is referred to as a curing agent A.

Production Example 2 Two OH-containing rosins (manufactured by Arakawa Chemical Industry Co., Ltd., CRW2
57) To 1149 g (1 mol) of TDI 348 g (2 mol) and dibutyltin dilaurate 1.50 g, 60
The addition agent is heated at 24 ° C. for 24 hours to obtain a hardening agent B which is a viscous liquid at room temperature.

Example 1 A polymer solution based on 2-ethylhexyl acrylate as an acrylic main agent (manufactured by Saiden Co., AT-
182 L-1, solid content 40%) 100 g, curing agent A of Production Example 1 0.60 g (based on 100 parts solid content of the main agent 1.50)
(Corresponding to parts) is added to obtain an acrylic pressure-sensitive adhesive.

Comparative Example 1 In Example 1, the TMP-3 was used instead of the curing agent A.
TDI compound (Nippon Polyurethane Co., Ltd., Coronate L)
An acrylic pressure-sensitive adhesive is obtained in the same manner except that 0.60 g is used.

Comparative Example 2 In Example 1, except that the curing agent A was replaced by 1.50 g of the same TMP-3TDI compound as in Comparative Example 1 and 15 g of the two OH-containing xylene resins (II) used in Production Example 1. To obtain an acrylic pressure-sensitive adhesive in the same manner.

Pressure-sensitive adhesive test (secondary evaluation) The pressure-sensitive adhesives of Example 1 and Comparative Examples 1 and 2 were applied to a polyethylene terephthalate film which had been surface-treated with an isocyanate-based primer in advance to give a dry film thickness of 30 μ. After drying and curing for 5 minutes, the film was attached to a stainless steel plate (SUS # 304), and the normal state (20
℃, 65% RH), as well as dry heat (70 ℃) or wet heat
180 after 7 days and 30 days under (50 ℃, 95% RH)
° Measure peel strength (kg / 25mm) (C / S = 300mm
/ Min). The results are shown in Table 1 below.

[0019]

[Table 1]

Examples 2 and 3 To 100 parts of the solid content of the same acrylic main agent (AT-182L-1) as in Example 1, 1.92 parts of the curing agent A of Production Example 1 or the curing agent B3. Add 33 parts to make the acrylic pressure-sensitive adhesives of Examples 2 and 3, respectively. As in the case of the above test, such an adhesive is applied to a polyethylene terephthalate film, dried and cured, and then adhered to a stainless steel plate to measure the 180 ° peel strength under normal conditions.

In addition, as a primary evaluation, after the adhesive is applied to a film and dried and cured, the adhesive surface is covered with release paper under dry heat (70 ° C.) or wet heat (50 ° C., 95% R).
After 7 or 30 days under H), peel off the release paper and stick it on a stainless steel plate to measure 180 ° peel strength, or apply the above adhesive to the film and dry as in the above test. A secondary evaluation is carried out in the state of being adhered to a stainless steel plate after curing and being placed under dry heat or wet heat for 7 days and 30 days. The results are shown in Table 2 below. The data for the primary and secondary evaluations under dry heat or wet heat are expressed as percentages (holding rate with time,%) when the normal strength is 100.

Comparative Examples 3 to 9 The same TMP-3TDI compound as in Comparative Example 1 and / or the number of parts shown in Table 2 was added to 100 parts of the solid content of the same acrylic main agent (AT-182L-1) as in Example 1. Two OH-containing xylene resins (II) (Nikanol K-100) as tackifying resins, two OH-containing rosins (CRW257),
Xylene resin or hydrogenated rosin was added to make the acrylic pressure-sensitive adhesive of each comparative example, the same evaluation as in Examples 2 and 3 was performed, and the results are shown in Table 2. In addition, * in Table 2 represents CF.

[0023]

[Table 2]

Claims (4)

[Claims] 1. An acrylic resin, characterized in that 0.05 to 5 parts by weight of a compound containing a tackifying component group and two isocyanate groups is added as a curing agent to 100 parts by weight of the solid content of the acrylic base material. System adhesive. 2. A compound containing a tackifying component group and two isocyanate groups has the formula: The acrylic pressure-sensitive adhesive according to claim 1, which is a compound represented by: 3. The formula: The compound represented by. 4. A process for preparing a compound according to claim 3, which has the formula: Xylene resin containing 2 hydroxyl groups of
A process for producing a reaction product, which comprises adding mol of 2,4-tolylene diisocyanate.