JPH02160884A - Self-adhesive tape - Google Patents

Abstract

PURPOSE:To obtain a self-adhesive tape capable of maintaining sufficient adhesive strength between same tape and an adherend by applying a composition consisting of a silanol-containing dimethylsiloxane, a curing agent, and an NCO compound to the area along the edges of a self-adhesive tape. CONSTITUTION:100 pts.wt. silanol-containing dimethylsiloxane (a) (e. g. a silicone having terminal silanol groups) is mixed with 0.01-5 pts.wt. curing agent (b) (e.g. triethylenediamine), an NCO compound (c) (e.g. 4,4'-diphenylmethane diisocyanate) in an amount sufficient to provide a molar ratio of the NCO group to the silanol group of component (a) of 0.7 to 10, and if necessary, a solvent (d), thus giving a composition. This composition is applied to the area along the edges of a self-adhesive tape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adhesive tape, for example, an adhesive tape for attaching side protection moldings (hereinafter referred to as moldings) to the body of an automobile.

[Conventional technology] Conventionally, the moldings attached to the side of the car body are
It is attached with double-sided adhesive tape.

On the other hand, wax is applied to the car body to protect the paint coated on the body surface.

Further, fuel such as gasoline is supplied to the fuel tank of the automobile through an injection port provided in a part of the body.

[Problems to be Solved by the Invention] However, wax remover is used when washing the car to wipe off wax applied to the surface of the car body, or wax remover is accidentally spilled when refueling with gasoline or other fuel. When these solvents such as wax remover and fuel adhere to the side edges of the double-sided adhesive tape, there is a problem in that the base material of the adhesive tape swells or dissolves.

Additionally, if the solvent attached to the side edges of the double-sided adhesive tape penetrates between the double-sided adhesive tape and the molding or between the double-sided adhesive tape and the body, the adhesive area between the two will become smaller. However, there was a problem in that the tensile shear strength and peel strength decreased.

For example, a coated steel plate and a vinyl chloride resin plate bonded using the double-sided adhesive tape are immersed in gasoline or wax remover at room temperature (23°C) for 1 hour, and then the bonded area and tensile shear strength are measured. As a result, the adhesive area was 1
00% to 25% and tensile shear strength from 8.8 kg/cut to 1.5 kg/c
It decreased to sA.

The purpose of the present invention is to prevent the base material of an adhesive tape from swelling or dissolving due to solvents such as wax remover and fuel, and to prevent the solvent from penetrating between the adhesive tape and the adherend. It is an object of the present invention to provide an adhesive tape that can prevent such problems and sufficiently maintain adhesive strength such as tensile shear strength and peel strength between the adhesive tape and an adherend.

[Means for Solving the Problems] In order to achieve the above object, the adhesive tape of the present invention is made of dimethylsiloxane containing a silanol group, a curing agent, and a compound containing an isocyanate group (-N GO). The composition is applied to the side edges.

[Detailed explanation of means] Dimethylsiloxane is a siloxane bond (Si-0-
Refers to a chain or cyclic silane compound having 3i). The dimethylsiloxane used in the present invention has a silanol group (-3IOH), and for example, silicone having a silanol group at the end is used.

The hardening agent is a compound that hardens the dimethylsiloxane, such as triethylenediamine (TEDA).
, N,N-dimethylbenzylamine, N,N-dimethyllaurylamine, N,N-dimethylpiperazine, N,N
, N', N'-tetramethylethylenediamine, N, N
, N', N'-tetramethylpropyldiamine, tetra-n-butyltin, trilobe chirutin acetate,
Trimethyltin hydroxide, dibutyltin dilaurate, stannath octoate, dibutyltin dilaurate 2
- Ethylhexoate, dibutyltin maleate, zinc octylate, iron octylate, cobalt octylate, lead octylate, etc. are used.

The blending ratio of the curing agent is preferably in the range of 0.01 to 5 parts by weight per 100 parts by weight of dimethylsiloxane having a silanol group. The blending ratio of this curing agent is 0.01
If it is less than 5 parts by weight, the polymerization rate will be slow and the rainwater properties, sealing properties, etc. of dimethylsiloxane will not be sufficiently exhibited, and if it exceeds 5 parts by weight, the curing agent will become an impurity and performance will deteriorate.

Next, compounds containing isocyanate groups will be explained.

As a compound containing an isocyanate group, a urethane prepolymer is synthesized by reacting a polyester polyol or a polyether polyol with a polyisocyanate,
Polyurethane reacted with a low molecular weight polyol can be used as a chain extender if necessary. Moreover, compounds containing isocyanate groups such as the above-mentioned polyisocyanates can also be used.

Examples of the polyester polyol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 2゜3-butanediol,
Diethylene glycol, dipropylene glycol, triethylene glycol, 1.5-bentanediol, 1.
1 such as 6-hexanediol, neopentyl glycol, etc.
species or a mixture of two or more species, and one of succinic acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, and isophthalic acid.
Those obtained by reacting a species or a mixture of two or more species are used.

The polyether polyols include polyoxypropylene glycol (PPG), polyoxyethylene glycol, polytetramethylene oxide glycol, propylene oxide adduct of glycerin, propylene oxide adduct of trimethylolpropane, and propylene oxide adduct of pentaerystol. etc. are used.

The polyisocyanate includes 2.4-tolylene diisocyanate, a ratio of 65/35 (24-tolylene diisocyanate and 2.6-)lylene diisocyanate,
The same applies hereinafter) Tolylene diisocyanate, 80/
20) lylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), dianisidine diisocyanate, tridene diisocyanate, hexamethylene diisocyanate, metaxylene diisocyanate, 1,5-naphthalene diisocyanate <NDI),
Hydrogenated 4,4'-diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated 2,4-tolylene diisocyanate, hydrogenated 65/35) lylene diisocyanate, hydrogenated 80/20 tolylene diisocyanate, isophorone diisocyanate, 4.4' , 4" triphenylmethane triisocyanate, tris(P-isocyanate phenyl) thiophosphate, etc. can be used.

In addition, examples of low molecular weight polyols having the function of a chain extender include ethylene glycol, propylene glycol, butanediol, bentanediol, hexanediol,
heptanediol, octanediol, diethylene glycol, triethylene glycol, dithioglycol,
Dipropylene glycol, neopentyl glycol, 2
-ethyl 2-n-butyl-1,3-propanediol,
2.2.4-) dimethyl-1,3-pencunediol, etc. can be used.

A compound containing an isocyanate group can be obtained by reacting the polyester polyol or polyether polyol with the polyisocyanate at 80° C. for 3 hours in dry nitrogen to obtain a urethane prepolymer, and reacting this with a low molecular weight polyol if desired. It is obtained by

The compounding ratio of the above-mentioned isocyanate group-containing compound is preferably such that the molar ratio of the isocyanate group to the silanol group of dimethylsiloxane is 0.7 to 10. If this molar ratio is less than 0.7, the resulting composition tends to have insufficient adhesive strength, and if it exceeds 10, the adhesive layer becomes too hard to function as an adhesive tape.

In the present invention, a solvent can be used if desired, and examples of the solvent include benzene, toluene, xylene, ethylbenzene, trichloroethylene, ethylene chloride, dimethylformamide (DMF), dimethyl sulfoxide, methyl ethyl ketone, methyl isopropyl ketone, Methyl isobutyl ketone, methyl acetate, ethyl acetate, isopropyl acetate, n-butyl acetate, anisole,
Chil ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, isopropyl acetate, Mn-butyl acetate, anisole, tetrahydrofuran, etc. can be used.

[Function] By employing the above means, the film formed on the side edge of the adhesive tape exhibits spraying properties, sealing properties, and solvent resistance due to the dimethylsiloxane cured by the curing agent, and also exhibits isocyanate It is presumed that the isocyanate group in the group-containing compound exhibits excellent adhesion between the adhesive tape and the adherend.

[Examples 1 to 7 and Comparative Examples 1 and 2] Examples embodying the present invention will be described below in comparison with comparative examples.

(1) Preparation of adhesive Polybutylene adipate (weight average molecular weight 9 approximately 2000)
200 parts by weight (hereinafter simply referred to as parts), 100 parts of 44゛-diphenylmethane diisocyanate, 300 parts of trichlorethylene, and 300 parts of dimethylformamide,
After reacting this in dry nitrogen at 80°C for 3 hours, 12.2 parts of ethylene glycol was added and reacted in dry nitrogen at 80°C for 20 minutes to obtain an adhesive.

(2) Preparation of adhesive 98 parts of butyl acrylate, 2 parts of acrylic acid, 0.2 parts of hendiyl peroxide, 90 parts of toluene, and 90 parts of ethyl acetate were mixed and reacted at 80° C. for 10 hours. Then, 2 parts of isophorone diisocyanate was added to 100 parts of this reaction solution to obtain an adhesive.

(3) Preparation of double-sided adhesive tape A base material is foamed polyethylene with a thickness of 1.0*n that has been expanded 10 times, and the adhesive is applied to one side and the adhesive is applied to the other side. Each was applied to obtain a double-sided adhesive tape.

Next, the isocyanate group-containing compounds used in each example will be explained.

(Example 1) MDI was used as a compound containing an isocyanate group.

(Example 2) As a compound containing an isocyanate group, 200 parts of polybutylene adipate (average molecular weight 2000), MD1
100 parts of DMF and 300 parts of DMF were reacted at 80°C for 3 hours in dry nitrogen.

(Example 3) As a compound containing an isocyanate group, PPG10
100 parts of 0O (average molecular weight 1000), 1105 parts of ND, and 205 parts of DMF were reacted at 80° C. for 3 hours in dry nitrogen and used.

(Example 4) As a compound containing an isocyanate group, 18 parts of 1,4-butanediol was added to the reaction solution obtained in Example 3, and the mixture was reacted for 20 minutes in dry nitrogen.

(Example 5) As a compound containing an isocyanate group, 10 parts of 1,4-butanediol was added as a chain extender to the reaction solution obtained in Example 2, and the mixture was reacted for 20 minutes in dry nitrogen. It was used.

(Example 6) As a compound containing an isocyanate group, 80 parts of polyethylene adipate (PEA) (average molecular weight 800), 30 parts of MD I, and 330 parts of DMF were mixed, and a reaction was performed at 80° C. for 3 hours in dry nitrogen. I used something similar.

(Example 7) As a compound containing an isocyanate group, an adduct of 3 moles of tolylene diisocyanate to 1 mole of trimethylolpropane was used.

Next, a composition was prepared by blending dimethylsiloxane (silicone) containing a silanol group, a curing agent, and the above compound containing an isocyanate group in the proportions shown in Table 1 below.

Table=1 The abbreviations in Table 1 above have the following meanings.

■Nitriethylenediamine■:Stannas octoate■:Zinc octylate■;Iron octylate■Nidibutyltin dilaurate■;Dibutyltin malate■: Tetra n-butyltin*Molar ratio of isocyanate groups to silanol groups of Nidimethylsiloxane Preparation The compositions of the above-mentioned examples were applied to the side edges of the double-sided pressure-sensitive adhesive tape, and then left at room temperature for -1 week for testing. Then, the side coated with the adhesive of the double-sided adhesive tape was adhered to a painted steel plate, and the side coated with the adhesive was adhered to a vinyl chloride resin plate to prepare a test piece. As Comparative Examples 1 and 2, test pieces were similarly prepared using double-sided pressure-sensitive adhesive tapes that were not coated with the composition of the above examples.

Measurement of adhesive area and tensile shear strength After each test piece was immersed in gasoline and wax remover as solvents for 1 hour at room temperature of 23°C, the adhesive area and tensile shear strength were measured at a tensile rate of 50 w/win. was measured. Furthermore, as Comparative Examples 1 and 2, the adhesive area and tensile shear strength were measured under the same conditions for test pieces in which the above-mentioned composition was not applied to the side edges of the double-sided adhesive tape. The measurement results are shown in Table-2.

As can be seen from Table 2 above, in Comparative Examples 1 and 2, in which the composition of each Example was not applied, the adhesive area was 25% and the tensile shear strength was as low as 1.5 kg/cnl. In Examples 1 to 7 of the present invention, the adhesive area was 92 to 97% for any solvent, and the tensile shear strength was 7.6 to 8.2.
High at kg/c4. This indicates that solvents such as gasoline and wax remover do not penetrate between the double-sided adhesive tape and the painted steel plate, or between the double-sided adhesive tape and the vinyl chloride resin plate, and the adhesion between them is poor. It can be seen that it is well maintained.

This is because the coating formed by applying the composition of each example to the side edge of the adhesive tape has water repellency, sealing performance, and solvent resistance due to the dimethylsiloxane cured with each curing agent. At the same time, a compound having isocyanate groups, for example, a compound whose chain is extended two-dimensionally and three-dimensionally by blending a polyol as a curing agent with a urethane prepolymer having isocyanate groups, can exhibit k'tlF-agent properties. It is thought that this is because the isocyanate group in the molecule not only improves the adhesiveness but also exhibits excellent adhesion between the adhesive tape and the adherend.

Therefore, if a molding is attached to the side of an automobile body using a double-sided adhesive tape coated with the composition of each example, even if gasoline or wax remover adheres to the side edge of the double-sided adhesive tape, However, due to the water repellency, adhesion, and solvent resistance of the same composition, various solvents may penetrate between the double-sided adhesive tape and the molding, and between the double-sided adhesive tape and the body. This prevents the molding from easily peeling off from the body.

Note that the present invention is not limited to the above embodiments,
Any changes may be made without departing from the spirit of the invention, and for example, the following configuration may be possible.

That is, the adhesive tape of the present invention, in addition to the adhesive tape used for attaching the molding of an automobile to the body in the above embodiment, is also suitable for chemical equipment and kerosene to which solvents such as toluene and xylene may adhere. It is also used as an adhesive tape for use on potentially dangerous parts.

[Effects of the Invention] The adhesive tape of the present invention can effectively prevent the base material of the adhesive tape from swelling and dissolving due to solvents such as wax remover and fuel, and the adhesive tape and the adherend can be effectively prevented from swelling or dissolving. This has excellent effects in that it can sufficiently prevent the solvent from penetrating between the adhesive tape and the adherend, and it can sufficiently maintain adhesive strength such as tensile shear strength and peel strength between the adhesive tape and the adherend.

Patent applicant: Toyoda Gosei Co., Ltd. Agent: Patent attorney: Hironobu Onda

Claims (1)

[Claims] 1. An adhesive tape prepared by coating the side edges with a composition comprising dimethylsiloxane containing a silanol group, a curing agent, and a compound containing an isocyanate group (-NCO).