JPH0481487A - Pressure sensitive adhesive composition and cured product thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to pressure sensitive adhesive compositions, and more particularly to elastic pressure sensitive adhesive side compositions that can be cured at or above room temperature.

(Prior Art) Silicone pressure-sensitive adhesives have traditionally been required to 1) have a sufficiently low working viscosity, 2) be able to cure at room temperature, and 3) provide not only wet tack but also dry tack. 4) to harden into a long-life product; and 5) to not disintegrate under humid conditions. However, it is difficult to satisfy all of these properties. It was difficult.

Therefore, the inventors conducted extensive studies to satisfy all of the above requirements, and as a result, they found a composition that could satisfy all of the above conditions and arrived at the present invention.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a room temperature-curing pressure-sensitive adhesive having a sufficiently low working viscosity and capable of imparting not only wet tack but also dry tack. It is an object of the present invention to provide a pressure-sensitive adhesive composition that does not disintegrate even under humid conditions after curing and is a long-lasting product, and a cured product thereof.

The above object of the present invention is to achieve at least ■R1S io, 7
consisting essentially of 8 units and 5iOa/z units, each 5i
An organosiloxane polymer having a molar ratio of R, S i O,, units to Onzx units of 0.6-1.2 and having less than 0.7% by weight of hydroxysilyl groups:
100 parts by weight, ■ An organopolysiloxane having an average formula whose molecular chain end is capped with a silyl group having a functional group of an alkoxy group, an alkenyloxy group, an iminoxy group, an acyloxy group, an aminoxy group, or an amine group. , the molar ratio of the silanol (St-OH) contained in the polymer of component (1) and the terminal group X of component (2) is 1<1.
(S1-0H)/X It was done.

1JIn the formula of the resinous organosiloxane copolymer having one component, each R independently represents methyl, ethyl, propyl,
Monovalent hydrocarbon groups having 1 to 6 carbon atoms, such as alkyl groups such as isopropyl, hexyl, cycloalkyl groups such as cyclohexyl, alkenyl M such as vinyl, 71J, perobenyl, and aryl groups such as phenyl, Alternatively, it represents a substituted monovalent hydrocarbon group such as a chloromethyl group or a 3.3.3-trifluoropropyl group in which some or all of the hydrogen atoms of these groups are substituted with a halogen atom or the like.

The R groups may be the same or different.

Such copolymers are substantially free of volatile components and are obtained by cohydrolyzing and condensing a hydrolyzable triorgano-substituted silane with a hydrolyzable silane that does not contain R groups in an organic solvent. , is a well-known material in the art of organosilicon chemistry. The organic solvent is preferably one that can dissolve the resin copolymer, and typical organic solvents include toluene, xylene, methylene chloride, naphtha mineral spirit, and the like. In addition, in the present invention, instead of these organic solvents, low molecular weight siloxane and 50-2
A second component organopolysiloxane having a viscosity of ,000 cSt may be used.

The organopolysiloxane as the second component has an average end capped with a silyl group having a hydrolyzable functional group such as an alkoxy group, an alkenyloxy group, an iminoxy group, an acyloxy group, an aminoxy group, or an amino group. It is an organopolysiloxane having the formula %, and among these, those blocked with a silyl group having an alkoxy group are particularly preferable.

Ro in the above formula is each independently a monovalent hydrocarbon group having 1 to 6 carbon atoms or a halogen-substituted hydrocarbon group, and specific examples include alkyl groups such as methyl, ethyl, propyl, and butyl. , cycloalkyl groups such as cyclohexyl, alkenyl groups such as vinyl, allyl, aryl groups such as phenyl, or chloromethyl, chloropropyl, 1-chloro-, in which some or all of the hydrogen atoms of these groups are replaced with halogen atoms. 2-methylpropyl, 3,3
．． Mention may be made of groups such as 3-trifluoropropyl. The RI groups may be the same or different, but are preferably methyl groups. Examples of the terminal group X include alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, methoxyethoxy, and ethoxyethoxy, alkenyloxy groups such as vinyloxy, isopropenyloxy, and isobutenyloxy, dimethylketoxime, methylethylketoxime, Iminooxy group such as cyclohexanoxime, acyloxy group such as acetoxy group, propionyloxy group, butyryloxy group, aminoxy group such as N,N-dimethylaminoxy, N,N-diethylaminoxy, N,N-diethylamino, butylamino, etc. Examples include hydrolyzable functional groups such as amino groups. or,
a is 0 or 1.

The viscosity of the organopolysiloxane as the second component is determined by n, which represents the number of repeats of the diorganosiloxane unit in the above general formula, and is 300.0OOc at 25°C.
It is preferable to select n that gives a viscosity of St or less,
In the present invention, in particular, 50-10,0OOcS at 25°C
Preferably, the fluid has a viscosity of t.

In addition, the amount of the second component used is the terminal group of the second component =S
Silanol 1&(=S
If the molar ratio of tOH) is less than 1, the pressure-sensitive adhesive properties of the cured rubber will decrease, whereas if this molar ratio is more than 10, curing will hardly occur. It is necessary to satisfy <=S i OH/X<10, preferably 4≦mi5iOH/X≦8.

The third component condensation catalyst is a metal carboxylic acid such as zinc octoate, lead 2-ethylhexanoate, dibutyltin diacetate, diptyltin dilactate, stannous octoate, zinc naphthenate, and ferrous octoate. selected from the group consisting of salts; The amount of catalyst used is 0.01 to 3 parts by weight based on 100 parts by weight of the first component resin copolymer.

A dimethylpolysiloxane fluid end-capped with trimethylsilyl groups or a low molecular weight cyclic siloxane may be added to the composition of the present invention for the purpose of adjusting the viscosity. It is effective to use 0OOcSt.

When using the composition of the present invention, an organic catalyst may be added, but care should be taken when using it, as ripples may occur due to evaporation of the solvent during curing, especially when curing by heating. is necessary.

Other materials known in the pressure sensitive adhesive industry may optionally be added to the compositions of the present invention, such as plasticizers, cosolvents, other silicone or organic pressure sensitive adhesives, etc. . Examples of organic pressure sensitive adhesives include natural rubber, styrene butadiene rubber, acrylonitrile rubber,
Examples include polyurethane rubber and polyisobutylene. They either have dry tackiness by themselves or develop such tackiness by adding plasticizers.

The compositions of the present invention contain guar gum, karaya, etc. to provide wet tack and water absorption properties.
rubber, locust bean
Water-soluble hydrocolloids such as gums, pectins, or mixtures thereof may also be included. Furthermore, even if hydrocolloids diluted with various solvents are used for the purpose of accelerating curing, fumed silica,
Reinforcing or bulking fillers such as precipitated silica, diatomaceous earth or feed may also be included.

When preparing the pressure-sensitive adhesive composition of the present invention, it is necessary to mix the organopolysiloxane as the second component and the condensation catalyst as the third component at the time of use, and in what order to mix each component. This is because the coexistence of the organopolysiloxane fluid as the second component and the condensation catalyst as the third component initiates the curing reaction.

That is, since the condensation catalyst can be mixed in advance with components other than the organopolysiloxane, which is the second component, when using the condensation catalyst, the other components other than the condensation catalyst can be uniformly mixed, and then this mixture and the condensation catalyst can be mixed. Ideally, the catalyst should be uniformly mixed with the mixture containing the catalyst.

(Effects of the Invention) The pressure-sensitive adhesive composition of the present invention has good workability because the viscosity of the composition can be adjusted appropriately, and it also has wet tackiness and dry tackiness. The range of applications can be expanded more than ever before. Moreover, the cured product does not disintegrate even under humid conditions and has a long life.

(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

In addition, all parts in the examples mean parts by weight.

Example 1 The end was blocked with a trimethoxysilyl group and the temperature was 1.0 at 25°C.
Trimethylsiloxy units ((CH
s)s S io, 7 units) and 3i04zx units, (CH3)! s io17□/S 10 ay□ molar ratio is 0°74, silanol group content is 0.06 mo
17,100 g of resinous siloxane copolymer dissolved in toluene to a solids content of 60% by weight,
As shown in Table 1, after weighing a predetermined amount within the range of 100 parts to 600 parts and stirring and mixing them uniformly, 0.1 part of dibutyldimethoxytin is added to 100 parts of the above mixture, and the mixture is further stirred uniformly. did.

Pour this into a 25m x 100 x 2 x 20°C
After curing for 7 days at 55RH%, the PET film was
After applying a load of 100 kg and leaving it for 20 minutes or more, the peeling force was measured in the 0-180 degree direction at a speed of 300 yen/1 minute.

The results are shown in Table 1.

Example 2 The terminal was blocked with a trimethoxysilyl group and the temperature was 1.0 at 25°C.
To 100 parts of a dimethylpolysiloxane polymer having a viscosity of OOcP, we weighed 200 parts of a resinous siloxane copolymer, similar to that used in Example 1, dissolved in toluene to a solids content of 60% by weight. After stirring uniformly, dimethyl dioctoxytin was added in a predetermined amount in the range of 0.1 to 0.9 parts based on 100 parts of the above mixture, and the mixture was further stirred and mixed uniformly. This was cured and measured under the same conditions as in Example 1, and the results are shown in Table 2.

The results in Table 2 demonstrate that adhesion is highly dependent on the amount of catalyst used.

Claims (1)

[Claims] 1) (1) R_3SiO_1_/_2 units (in the formula, each R
independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms. ) and SiO_4_/_2 units, R_3 for each SiO_4_/_2 unit
Organosiloxane polymer having a molar ratio of SiO_1_/_2 units of 0.6-1.2 and having less than 0.7% by weight of hydroxysilyl groups: 100 parts by weight, (2) Average formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R' independently represents a monovalent hydrocarbon group having 1 to 6 carbon atoms or a halogen-substituted hydrocarbon group, and X is an alkoxy group, alkenyloxy group, iminoxy group, acyloxy group, or aminoxy group. , represents at least one group selected from amino groups, a is 0 or 1, and n is 50 to 300,000 c of the organopolysiloxane at 25°C.
An organopolysiloxane having an average value of viscosity of A pressure-sensitive adhesive composition characterized by containing an amount used in a ratio such that 1<(Si-OH)/X<10, and (3) a condensation catalyst: 0.01-3 parts by weight. thing. 2) A cured product obtained by curing the composition according to claim 1).