JP3136941B2 - Method for manufacturing eyeglass pad - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing spectacle pads in which silicone rubber is integrated with a pad body made of a polycarbonate resin or a composition containing the resin.

[0002]

2. Description of the Related Art
As an eyeglass pad, a pad in which silicone rubber is coated on a pad body made of a synthetic resin from the viewpoint of fit and anti-slip properties is widely used.

In order to obtain a spectacle pad in which the silicone rubber is coated on the pad body, it is necessary that the silicone rubber does not peel off from the pad body. Is applied, and a silicone rubber composition is injected thereon to perform heat curing, or a through hole is provided in the pad body, and the silicone rubber composition is injected from above, and the silicone rubber composition and the pad in the hole are provided. 2. Description of the Related Art A silicone rubber composition coated on a main body is cured by heating to prevent the silicone rubber in the pad main body from being peeled off by a method of integrally connecting the silicone rubber and the silicone rubber coating the same.

However, in the former method, it takes time and effort to apply a primer to the pad body. In the latter method, the pad body and the silicone rubber are not basically adhered to each other. Are not adhered to each other, and if sebum enters between the pad body and the silicone rubber, the eyeglass pad swells, and the silicone rubber may be ruptured by an impact.

Therefore, in order to solve these problems, a pad body preformed in a mold is arranged, and then a self-adhesive silicone rubber composition is injected, and then heat-cured to form a silicone body. Although a method for adhesively coating rubber is also conceivable, in this method, when the molded spectacle pad is removed from the mold, the silicone rubber adheres to the mold, and the mold releasability is poor, and the method is not practical. There is no sex.

SUMMARY OF THE INVENTION The present invention has been made in order to improve the above circumstances, and provides a silicone rubber injection mold for an eyeglass pad having excellent adhesion to a synthetic resin pad body in a short time by injection molding. Provided is a method for manufacturing a spectacle pad which can solve the problem of adhesion to a substrate and can be manufactured with a high yield.

[0007]

Means and Action for Solving the Problems The present inventors have
As a result of diligent studies to achieve the above object, when manufacturing an eyeglass pad in which a synthetic resin pad body is coated with silicone rubber and integrated, the pad body is formed with a polycarbonate resin or a composition containing the resin. The pad body includes: (a) an alkenyl group-containing organopolysiloxane; (b) an organohydrogenpolysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule; (c) a catalyst for addition reaction; A compound having at least one hydrogen atom directly connected to one silicon atom and at least one phenyl skeleton, and
By injection molding a liquid addition-type self-adhesive silicone rubber composition containing an adhesion-imparting component selected from a compound having at least one alkenyl group and at least one phenyl skeleton, the polycarbonate resin or the resin is contained. The silicone rubber is coated and integrated with the pad body made of the composition with good adhesiveness, and the silicone rubber has good adhesion to the pad body as described above. The present invention has been found to be able to release the molded spectacle pad from the mold without any hindrance, and therefore to mold a stable quality spectacle pad in a short time with good yield. It has been reached.

The present invention will be described below in more detail. The present invention relates to a method for manufacturing a spectacle pad in which a synthetic rubber pad body 1 as shown in FIG. In the present invention, the pad body 1 is formed of a polycarbonate resin or a composition containing the resin.

Here, as the polycarbonate resin,
A commonly used polycarbonate resin having no aliphatic unsaturated group may be used, but the adhesiveness is slightly poor without secondary vulcanization (sufficient adhesiveness can be obtained by secondary vulcanization),
Polycarbonate resins containing aliphatic unsaturated groups are particularly preferred because good adhesion can be obtained only by primary vulcanization.

The polycarbonate resin having an aliphatic unsaturated group suitably used in the present invention includes a main chain and a terminal group.
It is assumed that the aliphatic unsaturated double bond or triple bond contains at least one or more per molecule on average, but the triple bond is often inferior to the weather resistance and heat resistance of the resin, and the double bond is more preferable. is there. Any unsaturated double bond contained in the resin can be used as long as it is an olefin, but is preferably a vinyl group, an allyl group, an isopropenyl group, or the like, and is preferably not an internal olefin.

[0011] Such a polycarbonate resin in which the inside of the molecule is modified with an aliphatic unsaturated group may be prepared from a dihydric phenol having an aliphatic unsaturated bond as a raw material, or a aliphatic acid as a molecular weight regulator or a terminal stopper. Other than using a monofunctional compound having an unsaturated bond, or using both in combination, a solution method such as a production method similar to that of a conventional aromatic polycarbonate resin, an interfacial polymerization method, a pyridine method, and a chloroformate method is used. Those produced are preferably used, and in this case, those having a viscosity average molecular weight of 2,000 to 100,000, preferably 5,000 to 30,000 are suitable.

The unsaturated group-containing polycarbonate resin used in the present invention is preferably represented by the following general formula (A) as the dihydric phenol compound to be used.

[0013]

Embedded image

Specifically, 2,2-bis (4-hydroxy-3-allylphenyl) propane, 2,4-bis (4
-Hydroxyphenyl) -4-methyl-1-pentene,
2,4-bis (4-hydroxyphenyl) -4-methyl-2-pentene, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfone, bis (4 -Hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ketone, 1,1-bis (4-hydroxyphenyl)
Ethane, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A; BPA), 2,2-bis (4
-Hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4
-Hydroxy-3,5-dibromophenyl) propane,
2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3-
Bromophenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxyphenyl) ) -1-Phenylethane, bis (4-hydroxyphenyl) diphenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,7-bis (4-hydroxy-3-methoxyphenyl) -1 , 6-heptadiene-
3,5-dione (curcumin) and the like are exemplified. One of these dihydric phenol compounds may be used alone, or two or more of them may be used in combination.

On the other hand, examples of the monofunctional compound having an unsaturated double bond used for introducing an unsaturated terminal group include acrylic acid, methacrylic acid, vinyl acetic acid, 2-pentenoic acid, 3-pentenoic acid, Unsaturated carboxylic acids such as 5-hexenoic acid, 9-decenoic acid and 9-undecenoic acid; acid chlorides or chloro acids such as acrylic acid chloride, methacrylic acid chloride, sorbic acid chloride, allyl chloroformate and isopropenylphenyl chloroformate; Formates; phenols having an unsaturated group such as isopropenylphenol, hydroxystyrene, o-allylphenol, eugenol, hydroxyphenylmaleimide, hydroxybenzoic acid allyl ester; dimethoxyvinylsilane chloroformate, 3-carboxylpropyldiethoxyvinyl Vinyl silanes such as orchids and the like. These compounds can be used in combination of two or more. Incidentally, as long as the condition that at least one unsaturated double bond is contained per one molecule of the polycarbonate resin average is satisfied, it is possible to change to a conventional terminal terminating agent such as phenol or p-tert-butylphenol, or to use unsaturated double bond. You may use together with the monofunctional compound which has a bond. The terminating agent is used in an amount of usually 1 to 25 mol%, preferably 1.5 to 25 mol%, per 1 mol of the dihydric phenol compound.
It is used in the range of 10 mol%.

Further, the branching agent is used in an amount of 0.01 to 3 mol%, preferably 0.1 to 1 mol%, based on the above dihydric phenol compound.
A branched polycarbonate can be used in combination in the range of mol%. Phloroglucin, as a branching agent,
2,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-3,4,6-dimethyl-2,4
6-tri (4-hydroxyphenyl) heptene-2,
1,3,5-tri (2-hydroxyphenyl) benzol, 1,1,1-tri (4-hydroxyphenyl) ethane, 2,6-bis (2-hydroxy-5-methylbenzyl) -4-methylphenol , Α, α ′, α ″ -tri (4-hydroxyphenyl) -1,3,5-triisopropylbenzene and 3,3-bis (4-hydroxyphenyl) oxindole (= Isatin bisphenol) and the like.

The above-mentioned unsaturated group-containing polycarbonate resin is preferably used for the integrally molded body of the polycarbonate resin and the silicone rubber of the present invention. ) Can be used.

The silicone rubber composition for obtaining the silicone rubber integrated with the polycarbonate resin or a composition containing the resin includes: (a) an alkenyl group-containing organopolysiloxane (b) an organohydrogenpolysiloxane (c) Use is made of a liquid addition-type self-adhesive silicone rubber composition containing an addition reaction catalyst (d) an adhesion-imparting component.

Here, as the organopolysiloxane containing an alkenyl group as the component (a), a known organopolysiloxane used as a main raw material of an addition-type silicone rubber composition can be used. This alkenyl group-containing organopolysiloxane has a viscosity of 100 at room temperature.
It is preferable to use one having a centipoise of １００100,000 centipoise.

As the organopolysiloxane, those represented by the general formula R _a SiO _{(4-a) / 2} are particularly preferably used. In this formula, R is a substituted or unsubstituted monovalent hydrocarbon group, preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms. Specifically, alkyl groups such as methyl, ethyl and propyl; alkenyl groups such as vinyl, propenyl and butenyl; aryl groups such as phenyl and xylyl;
Examples thereof include halogen-substituted and cyano-substituted hydrocarbon groups such as trifluoropropyl. The monovalent hydrocarbon groups may be different or the same, but it is necessary that the molecule contains an alkenyl group. In this case, the amount of the alkenyl group is 0.01 to 10 mol% in R, particularly 0.1
It is preferably about 1 mol%. A is 1.9 to
2.4, and this organopolysiloxane may have a linear structure, or may further have RSiO _3/2 units or SiO 2
_It may be branched containing _4/2 units. The substituent of the silicon atom may be basically any of the above, but it is preferable to introduce a vinyl group as the alkenyl group and to introduce a methyl group or a phenyl group as the other substituent.

Examples of such an organopolysiloxane include the following.

[0022]

Embedded image (Wherein R has the same meaning as described above (excluding aliphatic unsaturated groups), and m and n are integers of 0 or more, provided that m + n =
100-5000, if there is m, m / (m + n) =
0.001 to 0.1. )

The organohydrogenpolysiloxane of the component (b) reacts with the component (a) and acts as a crosslinking agent. In the present invention, the organohydrogenpolysiloxane contains a hydrogen atom directly bonded to at least two silicon atoms in one molecule, but there is no particular limitation on the molecular structure, for example, linear, cyclic or branched. Various known structures and the like can be used. The viscosity is preferably 300 cs or less.

In this organohydrogenpolysiloxane, examples of the silicon atom-bonded substituent other than the hydrogen atom bonded to the silicon atom include those similar to R in the above formula (1). Those having no unsaturated bond are preferred.

The amount of component (b) added is such that hydrogen atoms directly bonded to silicon atoms are contained in alkenyl group 1 contained in component (a).
The amount is 0.4 to 5 equivalents, preferably 0.8 to 2 equivalents. If the amount is less than 0.4 equivalent, the crosslinking density becomes too low, which may affect the heat resistance of the cured silicone rubber. If the amount is more than 5 equivalents, a problem of foaming due to a dehydrogenation reaction may occur, or the heat resistance may be adversely affected.

Next, examples of the catalyst for the addition reaction of the component (c) include platinum and a platinum compound, and these are the curing addition reaction (hydrocystylation) of the components (a) and (b) described above. Known catalysts can be used, for example, platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, and a mixture of chloroplatinic acid and olefin ,
Examples thereof include complexes of aldehyde, vinyl siloxane, and acetylene alcohols. Further, a rhodium complex or the like can also be used. The amount of these addition reaction catalysts is not particularly limited, and can be appropriately selected depending on the desired curing speed. Usually, the amount of platinum or rhodium is 0.1 to 10% based on the total amount of all components. 1 to 10
It is preferable to use within the range of 00 ppm, preferably 1 to 200 ppm.

Further, the component (d) used in the present invention for imparting adhesiveness has good adhesiveness to a polycarbonate resin or a composition containing the resin, which forms the pad body, and also to a metal. On the other hand, a material showing non-adhesion or poor adhesion is used. Specifically, it is effective to use a compound having no functional group capable of adhering to a metal, such as a dialkoxysilane, a trialkoxysilyl group, or a glycidyl group. From the viewpoint of affinity, a compound having at least one, preferably two or more hydrogen atoms directly bonded to silicon atoms and at least one phenyl skeleton in one molecule, and at least one alkenyl group (preferably carbon It is preferable to use a compound having Formulas 2 to 3) and at least one phenyl skeleton.
Compounds having a group selected from (6) are preferred.

[0028]

Embedded image

[0029]

Embedded image

Examples of the monovalent hydrocarbon group of R ^{11 to} R ²¹ include the same ones as those of R. Examples of the carbocycle and heterocycle in which R ²⁰ and R ²¹ are bonded include the following. No.

[0031]

Embedded image Examples of such an adhesion-imparting component include the following.

[0032]

Embedded image

[0033]

Embedded image

The amount of the component (d) is not particularly limited and may be appropriately selected. The amount is 0.01 to 50 parts by weight, particularly 0.1 to 5 parts by weight, per 100 parts by weight of the component (a). Is preferred. If the amount is less than 0.01 parts by weight, the adhesion to the polycarbonate resin is not sufficient, and
If the amount is more than 50 parts by weight, physical properties of the silicone rubber may deteriorate.

In the present invention, in order to obtain a spectacle pad, a pad body made of a polycarbonate resin or a composition containing the resin molded by an ordinary method is fixed to a spectacle pad mold, and the above-mentioned pad is placed in the mold. A method in which a liquid addition-type self-adhesive silicone rubber composition containing (a) to (d) is injected to perform heat compression molding, a transfer molding method, and the like can be employed. In order to reduce the cost, the pad body is placed in a pad mold for spectacles, and then a silicone rubber composition is injection-molded, or a polycarbonate resin is first injected by a two-color molding machine, and an in-mold gate cut method is used. Unnecessary sprue,
A method in which the runner is removed outside the mold to form the pad body, the pad body is left in the mold, and then the silicone rubber composition is injection-molded in the mold can be more suitably adopted.

In the above manufacturing method, in order to further strengthen the adhesiveness between the pad body and the silicone rubber composition, the temperature at which the pad body is softened after the silicone rubber composition is heated and cured. It is preferable to perform the secondary vulcanization at a temperature equal to or lower than the softening temperature of the polycarbonate resin. In this case, the secondary vulcanization time is preferably 30 minutes to 4 hours, particularly preferably 1 to 2 hours.

[0037]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Examples 1 to 4, Comparative Examples 1 and 2 A polycarbonate resin containing about 3% of an aliphatic unsaturated group in a thermoplastic resin injection molding machine (SAV-30, manufactured by Yamashiro Seiki Seisakusho Co., Ltd.) And plasticized at 300 ° C., and then injected into an eyeglass pad mold at an injection time of 5 seconds, a cooling time of 20 seconds, and a mold temperature of 1
Injection was performed at 10 ° C. to form a pad body.

On the other hand, 100 parts by weight of a dimethylsiloxane polymer having a viscosity of 10,000 centipoise at 25 ° C. blocked at both ends with dimethylvinylsilyl groups, and 40 parts by weight of fumed silica having a specific surface area of 300 cm ² / g. , 8 parts by weight of hexamethyldisilazane and 1 part by weight of water were charged into a kneader, and the mixture was stirred and mixed at room temperature for 1 hour.
The temperature was raised to 150 ° C., and the mixture was kept warm for 2 hours. Thereafter, the mixture was cooled to room temperature, and 20 parts by weight of the dimethylsiloxane polymer and 3 parts by weight of methyl hydrogen polysiloxane having a viscosity of about 10 centipoise at room temperature represented by the following formula (A) were added thereto. Viscosity at room temperature containing 5 mol% of vinyl groups directly bonded to atoms is 10
4 parts by weight of vinylmethylpolysiloxane of 00 centipoise, 0.1 parts by weight of acetylene alcohol to extend the time until curing at room temperature, and 50 ppm of platinum-vinylsiloxane complex as platinum atoms are added to make the mixture uniform. This was mixed well to obtain a liquid addition type silicone rubber composition (I).

[0040]

Embedded image

The obtained composition (I) was pressed under a curing condition of 120 ° C./10 minutes to form a sheet, and the mechanical properties were examined. The results were as follows. Hardness (JIS-A) 40 Elongation 500% Tensile strength 100kgf / cm ² Tear strength 35kgf / cm

Next, to the composition (I) were added the adhesion-imparting components represented by the following formulas (B) to (F) in the amounts shown in Table 1 to prepare silicone compositions.

[0043]

Embedded image

Next, the pad body was placed in a pad mold for spectacles having a cavity portion subjected to hard chrome plating, and the silicone rubber composition was injected into the cavity for 5 seconds, a curing time of 30 seconds, and a mold temperature. Injection was performed at 120 ° C. to perform integral molding to produce a spectacle pad. Table 1 shows the results of examining the adhesiveness of the obtained spectacle pad. In addition,
For those with normal adhesion, after molding eyeglass pads,
Furthermore, vulcanization was performed at 120 ° C. for 1 hour, and the adhesion was examined in the same manner as above.

[0045]

[Table 1]

From the results shown in Table 1, the spectacle pad obtained by the method of the present invention for producing a spectacle pad shows good adhesion between the polycarbonate resin and the silicone rubber. It was also confirmed that the mold releasability was excellent.

[Examples 5 to 8, Comparative Example 3] Using a standard grade polycarbonate resin containing no aliphatic unsaturated group (Iupilon S3000, manufactured by Mitsubishi Gas Chemical Co., Ltd.), the same molding conditions as described above were used. A spectacle pad was formed by using the method described above, and its adhesiveness was examined. Table 2 shows the results.

[0048]

[Table 2]

[0049]

According to the method for manufacturing a spectacle pad of the present invention, the adhesion between the pad body and the silicone rubber is excellent, and
Since it can be peeled off from the mold after molding, a spectacle pad can be efficiently obtained with good yield.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1 pad body 2 silicone rubber

Continuing from the front page (72) Inventor Shigeyuki Shuto 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronics Materials Research Laboratory (56) References JP-A-62-32418 (JP, A) JP-A-6-271684 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/24 G02C 5/12

Claims (2)

(57) [Claims] When manufacturing a spectacle pad in which silicone rubber is integrated with a synthetic resin pad body, the pad body is formed from a polycarbonate resin or a composition containing the resin, and the pad body has a) an alkenyl group-containing organopolysiloxane; (b) an organohydrogenpolysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule; (c) an addition reaction catalyst; and (d) a direct bonding to at least one silicon atom. A compound having a hydrogen atom and at least one phenyl skeleton, and
Injection molding a liquid addition-type self-adhesive silicone rubber composition containing an adhesion-imparting component selected from a compound having at least one alkenyl group and at least one phenyl skeleton, and forming the self-adhesive silicone rubber on a pad body A method for producing a spectacle pad, comprising: 2. The addition-type self-adhesive silicone rubber composition is injection-molded, heat-cured, and then subjected to secondary vulcanization at a temperature lower than the temperature at which the pad body softens. The method for manufacturing a spectacle pad according to claim 1, wherein the rubber is integrated.