KR101712356B1 - Rubber Composition of Excellent Cavity-filling and Demolding Property - Google Patents

Abstract

The present invention relates to a release-type rubber composition for imparting releasability to a mold, and more particularly, to an environmentally-friendly and highly functional mold release-type rubber composition having improved filling property and deformation, and more particularly to a rubber composition containing a butadiene rubber, an ethylene- The present invention relates to a release type rubber composition comprising an uncrosslinked rubber and a wax including a specific polymer additive capable of improving the mobility in the mold of the monomer rubber and the rubber composition, a curing agent and an inorganic filler, will be.

Description

[0001] The present invention relates to a rubber composition of Excellent Cavity-filling and Demolding Property,

The present invention relates to a release-type rubber composition for imparting releasability to a mold, and more particularly, to a release-type rubber composition for improving mobility in a mold of a rubber composition by combination of specific components, will be.

A mold used for molding a product by using a thermosetting resin as a raw material by compressing and heating it is a carbon material that remains as a part of the contaminants and the molding material flowing during the working process, Not only cause some defects in the molded product, but also cause the quality of the product to deteriorate during the continuous molding process. Therefore, a cleaning operation for removing the contaminants remaining in the mold must be performed after the molding operation is performed for a predetermined period to a predetermined number of times, and in addition, a releasing property should be imparted to the mold in order to facilitate detachment of the thermosetting resin Work (so-called "release work") is essential.

Particularly, in the EMC molding process for manufacturing semiconductors, the mold releasing operation directly affects the quality of the semiconductor device. When the releasability given to the surface of the mold does not reach a certain level, Since it takes time, studies have been conducted to maintain the mold for a long time while imparting releasability to the mold.

Conventionally, in order to impart releasability to a mold, natural canova wax or dimethyl silicone oil pulverized into a powder state is mixed with a solvent such as a nucleic acid, and the mixture is sprayed directly onto the surface of a mold by placing it in a high-pressure spray container. And a method of coating this with a low-pressure transfer molding method.

However, when the above methods are used, it is not uniformly applied to the inside of the mold, resulting in a decrease in releasability, environmental pollution due to the use of nucleic acid solvent, and excessive cost incurred in the low-pressure transfer molding method do.

One solution to solve this problem is to use an uncrosslinked rubber containing a butadiene rubber (BR) and an ethylene-propylene diene monomer rubber (EPDM) as a base and a mold coating further comprising a coating component, an inorganic filler, There has been proposed a mold coating method by eluting a coating component (wax and an additive) according to rubber hardening through a rubber composition for a rubber composition.

1 is a schematic view showing a release rubber mechanism and non-fill property of a conventional rubber composition, and FIG. 2 is a photograph showing a crosslinked rubber deformed from a mold in the process of FIG. 1, FIG. 3 is a schematic view showing the process of manufacturing the EMC product through the coated mold through the process of FIG. 1 and the failure of the EMC product due to the non-fill property.

1 to 3, a release rubber composition 120 including an uncrosslinked rubber 121 and a coating component 122 is placed in a mold 110 and then cured at a temperature of about 175 to 180 ° C The cross-linking reaction proceeds, and when the cross-linked rubber 130 is removed, the inside of the mold 110 is coated with the coating component 122.

However, the above-mentioned method is problematic in that the mold 110 has a problem of product failure and contamination of the mold due to deterioration of the deformation of the rubber which can not be easily removed from the composition, and that the portions 110a There is a problem in that the releasability of the mold is lowered due to non-fill phenomenon in which the rubber composition is not sufficiently filled.

Therefore, there is a high need for a rubber composition that not only reduces manufacturing cost in the mold release agent coating operation, provides an environment friendly working environment, but also exhibits excellent de-molding and filling properties.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

As will be described later, it is confirmed that the rubber composition according to the present invention is composed of a combination of specific components, and that when such a rubber composition is used in a molding die, the mold releasing and filling property of the releasing rubber is excellent, I have come to completion.

To achieve the above object, the rubber composition according to the present invention is a rubber composition for improving the releasability of a molding die,

60 to 100 parts by weight of a butadiene rubber (BR), 0 to 40 parts by weight of an ethylene-propylene diene monomer rubber (EPDM) and 5 to 40 parts by weight of a polymer additive having a melting temperature ( _Tm ) And

5 to 60 parts by weight of a wax, 0.5 to 10 parts by weight of a curing agent and 5 to 110 parts by weight of an inorganic filler and an adsorbent based on 100 parts by weight of the uncrosslinked rubber;

And a control unit.

Here, the melting temperature means a peak point obtained by DSC (Differential Scanning Calorimeter) analysis. Uncrosslinked rubber is crosslinked in the mold by the action of the hardener when heat and pressure are applied, and the inside of the mold is treated with wax and additives Means the component to be removed after coating.

The rubber composition according to the present invention further improves the mobility of the rubber composition by further including the butadiene rubber used as the base material of the conventional uncrosslinked rubber and the polymer additive satisfying the specific conditions for the ethylene-propylene diene monomer rubber, The filling property of the rubber can be improved, so that it is possible to completely coat the inside of the mold with the wax and the additive, so that the de-formation of the rubber produced through the composition can be enhanced.

As described above, the uncrosslinked rubber in the rubber composition may contain no ethylene-propylene diene monomer rubber, or may be contained in an amount of 40 parts by weight or less. Specifically, the content of the uncrosslinked rubber in the rubber composition may be 5 to 30 parts by weight .

The polymer additive may be included in an amount of 5 to 40 parts by weight, specifically 10 to 30 parts by weight.

If the amount of the polymer additive is more than 40 parts by weight in the uncrosslinked rubber, the degree of crosslinking of the releasing rubber is lowered, the amount of the wax and the additive coated in the mold becomes small, resulting in a problem of releasability. On the other hand, Is contained in an amount of less than 5 parts by weight, there is a problem that the present invention hardly exhibits the desired level of filling property and deformation.

In one specific example, the polymer additive may have its melting temperature in the range of 40 ° C to 100 ° C, and more specifically in the range of 40 ° C to 90 ° C.

Exceeding the above range, when the polymer melting temperature exceeds 100 ° C, the production temperature becomes high and scorch (pre-crosslinking) occurs in the production of uncrosslinked rubber product, resulting in product failure. On the other hand, when the melting temperature of the polymer additive is 40 ° C, the surface of the product becomes sticky, which causes the product to stick to the surface of the equipment during the production process. As a result, it is difficult to produce the product and the hardness of the product is lowered and the filling property is deteriorated .

In one specific example, the polymer additive is a copolymer comprising a polyolefin-based elastomer or a copolymer composed of a monomer for a polyolefin and an acrylic acid monomer, an ionomer thereof, or a monomer for a polyolefin and an acrylate monomer .

The polyolefin elastomer is not particularly limited as long as it satisfies the conditions of the above-described polymer additive, and examples thereof include ultra low density polyethylene (VLDPE); Polybutene; Poly-4-methyl-1-pentene (TPX); Copolymers of propylene, butene, hexene and / or octene with ethylene; And an olefinic thermoplastic elastomer. Accordingly, a copolymer comprising a low density polyethylene (LDPE), an ultra low density polyethylene (VLDPE) or a monomer for a polyolefin and an acrylic acid monomer having a melting temperature exceeding 100 DEG C, and a copolymer comprising the monomer for the ionomer or polyolefin and the acrylate monomer , It may not be suitable for the polymer additive of the present invention.

The copolymer composed of the monomer for polyolefin and the acrylic acid monomer, and the copolymer comprising the monomer for the ionomer or polyolefin and the acrylate monomer is not particularly limited as long as it satisfies the above-mentioned condition that the melting temperature (T _m ) is 100 ° C or less , An ethylene-acrylic acid copolymer (EAA), an ethylene-methacrylic acid copolymer (EMAA) and its ionomer, an ethylene-methyl acrylate copolymer (EMA), an ethylene-ethyl acrylate copolymer (EEA) (EBA), and an ethylene-vinyl acetate copolymer (EVA). The ethylene-vinyl acetate copolymer may be at least one selected from the group consisting of a polyacrylic acid copolymer, a polyacrylic acid copolymer, a polyacrylic acid copolymer, a methacrylic acid copolymer,

The copolymer may be, for example, a composition comprising 60 to 96% by weight of a monomer for polyolefin based on 100% by weight of the copolymer and 4 to 40% by weight of acrylic acid or an acrylate or vinyl acetate monomer.

In one specific example, the polyolefin elastomer as the polymer additive may be an ethylene-propylene copolymer or an ethylene-butylene copolymer obtained by the reaction of an ethylene monomer with a propylene monomer or a butylene monomer. It is needless to say that the ethylene-propylene copolymer or the ethylene-butylene copolymer satisfies the conditions of the polymer additive described above.

On the other hand, practically, the wax and the additive for imparting mold releasability to the mold are not particularly limited as long as they perform such action. For example, polyethylene and slip agent having a weight average molecular weight of 200 to 3000, , And an anti-blocking agent may be mixed. Here, the slip agent for improving the de-formation of the rubber is not particularly limited, but examples thereof include Erucamide, Oleamide, Stearamide, Behenamide, , Ethylene-bis-stearamide, ethylene-bis-oleamide, and stearyl erucamide.

The amount of the wax and the additive may be 5 to 60 parts by weight based on 100 parts by weight of the uncrosslinked rubber. If the amount is less than 5 parts by weight, it is difficult to impart sufficient releasability to the mold, If the amount is more than 60 parts by weight, surplus wax on the surface of the mold may leave uneven marks on the surface of the mold and serve as another contaminant.

The above-mentioned curing agent may be an organic peroxide, phenol resin, sulfur, or the like, which is a component serving to induce such curing when the uncrosslinked rubber is cured while undergoing a crosslinking reaction by heat and pressure. Specifically, it may be an organic peroxide, and the kind of the organic peroxide may be selected according to the mold temperature in consideration of the half-life temperature. Such organic peroxides include, but are not limited to, for example, 2,5-dimethyl-2,5-bis- (t-butylperoxy) t-butylperoxy), dt-butylperoxide, 2,5-dimethyl-2,5-bis- (t-butylperoxy) - (t-butylperoxy) -hexane, t-buthylcumylperoxide, bis- (t-buthylperoxy-i-propyl) benzene, dicumylperoxide, 4,4-di-t-buthylperoxy-n-buthylvalerate, t-butylperoxybenzoate, T-buthylperoxybenzoate, 1,1-di-t-buthylperoxy-3,3,5-trimethylcyclohexane, dibenzoyl- Di-benzoylperoxide, bis- (2,4-dichlorobenzoyl) -peroxide and the like can be used. Of these, bis (t-butylperoxy-i-propyl) benzene and 4,4-di-t-butylperoxy-n-butyl valerate are obtained by reacting ethylene-propylene diene monomer (EPDM) Lt; RTI ID = 0.0 > rubbers < / RTI >

As described above, the content of the curing agent is 0.5 to 10 parts by weight based on 100 parts by weight of the uncrosslinked rubber. When the amount of the curing agent is less than 0.5 parts by weight, the initiation of curing or the curing rate can not be promoted. There is a problem that mechanical properties such as tear strength are greatly decreased due to excessive crosslinking, which is undesirable.

The inorganic filler is a component that serves to increase the balance of the components of the composition as the viscosity increases. That is, by adding wax to the uncrosslinked rubber, the viscosity of the composition is lowered. An inorganic filler can be added to increase the Mooney viscosity and maintain balance among the various components. Examples of such an inorganic filler include silica, talc, alumina, potassium carbonate, calcium carbonate, aluminum hydroxide, titanium oxide, and carbon black.

In some cases, the rubber composition according to the present invention adsorbs and removes various odor and smoke components generated in the release operation (the operation of applying heat and pressure to a mold release rubber sheet made of the rubber composition according to the present invention) Gt; adsorbent < / RTI >

Such an adsorbent has a high adsorption power and a large specific surface area for the odor and smoke components. The odor and smoke generated during the operation are inevitably caused by various factors such as, for example, decomposition of the curing agent and decomposition of the detergent. In the composition according to the present invention, an adsorbent having fine pores and a large specific surface area is added The problem caused by this can be solved. The adsorbent has a specific surface area of at least 200 m 2 / g or more. In addition, it is possible to exhibit a more excellent adsorption force by having a lot of fine pores.

Examples of the adsorbent include clay (silica), silica gel, activated carbon, zeolite, ion exchange resin, acidic clay and the like. In some cases, they may be used in the form of a mixture of two or more thereof. In particular, the adsorbent used in the present invention may be zeolite, silica gel, or acidic white clay having a specific surface area of not less than 200 m < 2 > / g and not being colored. More specifically, it may be a fine powder silica gel or zeolite have. The fine powder silica gel can solve the problem of kneading with uncrosslinked rubber by pulverizing silica gel particles in micrometer (㎛) units in advance in meters (mm), and the zeolite X type and zeolite Y type have a specific surface area (about 500 ㎡ / g) is large, but it is expensive, so that the manufacturing cost of the composition of the present invention can be lowered by mixing with zeolite A type. On the other hand, since activated carbon and ion exchange resin have a very large specific surface area (about 600 m 2 / g or more), they are excellent in adsorption power, but are preferably used in combination with other adsorbent components since they are blackish and expensive.

The adsorbent may also function as an inorganic filler, and the content of the adsorbent and the inorganic filler may be 5 to 110 parts by weight based on 100 parts by weight of the uncrosslinked rubber.

In addition, the rubber composition according to the present invention may further contain other compound (s) or mixture (s) within a range not to impair its physical properties.

The rubber composition of the present invention improves the mobility of the rubber composition in a mold by combination of specific components. As a result, the filling property is improved, thereby solving the problems of the non-fill phenomenon of the prior art, Excellent effect is provided, and the effect of improving mold releasability is exhibited.

1 is a schematic view showing a release rubber mechanism and non-fill property of a conventional rubber composition;
FIG. 2 is a photograph showing a crosslinked rubber deformed from a mold in the process of FIG. 1; FIG.
FIG. 3 is a schematic view showing a process of manufacturing an EMC product through a coated mold through the process of FIG. 1 and a failure of the EMC product due to non-compatibility;
4 is a schematic view showing a release rubber mechanism of a rubber composition excellent in filling and deformation according to one embodiment of the present invention;
5 is a photograph showing a crosslinked rubber deformed from a mold in the process of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

FIG. 4 is a schematic view showing a mold releasing rubber mechanism of a rubber composition excellent in filling and deformation according to one embodiment of the present invention, and FIG. 5 is a photograph showing a crosslinked rubber deformed from a mold in the process of FIG. Respectively.

4 to 5, a release rubber composition 220 including an uncrosslinked rubber 221 and a coating component 222 is placed in a mold 210 and then cured at a temperature of about 175 to 180 ° C When the crosslinking rubber 230 is removed, the interior of the mold 210 is coated with the coating component 222.

At this time, unlike the conventional rubber composition, since the rubber composition is sufficiently filled in the portions 210a that are embedded in the mold, the non-fill phenomenon does not occur and the deformation is excellent. As a result, Shaped cross-linked rubber is deformed from the mold.

Hereinafter, the present invention will be described in detail with reference to examples, but the scope of the present invention is not limited thereto.

≪ Example 1 >

300 g of ethylene-propylene diene monomer rubber (EPDM) and 200 g of very low density polyethylene (VLDPE) were mixed and added to 700 g of butadiene rubber (BR) to obtain a curing agent (4,4-di-t-butylperoxy-n (300 g of silica, 50 g of titanium oxide), and wax (80 g of polyethylene, 20 g of slip) were kneaded in a roll mill with a kneader. At this time, the density of the ultra-low density polyethylene (VLDPE) is 0.87 and the melting temperature is 60 占 폚.

≪ Example 2 >

Except for using 200 g of an ionomer of an ethylene-methacrylic acid copolymer (EMAA) produced by reacting an ethylene monomer and an acrylic acid monomer at a weight ratio of 9: 1 in place of the ultra low density polyethylene (VLDPE) in Example 1 A kneaded product was prepared in the same manner as in Example 1. At this time, the ethylene-methacrylic acid copolymer (EMAA) had an ionomer density of 0.95 and a melting temperature of 70 占 폚.

≪ Example 3 >

Except that 200 g of the ethylene-methacrylic acid copolymer (EMA) produced by reacting the ethylene monomer and the methacrylic acid monomer at a weight ratio of 9: 1 was used instead of the ultra low density polyethylene (VLDPE) in Example 1 A kneaded product was prepared in the same manner as in Example 1. At this time, the density of the ethylene-methacrylic acid copolymer (EMA) is 0.94 and the melting temperature is 72 占 폚.

<Example 4>

Except that 200 g of an ethylene-vinyl acetate copolymer (EVA) produced by reacting an ethylene monomer and a vinyl acetate monomer at a weight ratio of 9: 1 was used in place of the ultra low density polyethylene (VLDPE) in Example 1 A kneaded product was prepared in the same manner as in Example 1. At this time, the density of the ethylene-vinyl acetate copolymer (EVA) was 0.95 and the melting temperature was 75 ° C.

&Lt; Example 5 >

A kneaded product was prepared in the same manner as in Example 1, except that the ethylene-butylene copolymer (200 g) was used instead of the ultra-low density polyethylene (VLDPE) in Example 1. At this time, the ethylene-butylene copolymer had a density of 0.88 and a melting temperature of 64 占 폚.

&Lt; Example 6 >

300 g of ethylene-propylene diene monomer rubber (EPDM) and 300 g of very low density polyethylene (VLDPE) were mixed and added to 700 g of butadiene rubber (BR) to obtain a curing agent (4,4-di-t-butylperoxy-n (300 g of silica, 50 g of titanium oxide), and wax (80 g of polyethylene, 20 g of slip) were kneaded in a roll mill with a kneader. At this time, the density of the ultra-low density polyethylene (VLDPE) is 0.87 and the melting temperature is 59 deg.

&Lt; Example 7 >

300 g of ethylene-propylene diene monomer rubber (EPDM) and 100 g of ultra-low density polyethylene (VLDPE) were mixed and added to 700 g of butadiene rubber (BR) to prepare a curing agent (4,4-di-t-butylperoxy-n (300 g of silica, 50 g of titanium oxide), and wax (80 g of polyethylene, 20 g of slip) were kneaded in a roll mill with a kneader. At this time, the density of the ultra-low density polyethylene (VLDPE) is 0.885 and the melting temperature is 80 ° C.

&Lt; Comparative Example 1 &

A kneaded product was prepared in the same manner as in Example 1, except that the ultra low density polyethylene (VLDPE) was not used in the above Example 1.

&Lt; Comparative Example 2 &

A kneaded product was prepared in the same manner as in Example 1 except that low density polyethylene (LDPE) was used in place of the ultra low density polyethylene (VLDPE) in Example 1. At this time, the density of the low density polyethylene (LDPE) is 0.921 and the melting temperature is 110 占 폚.

&Lt; Comparative Example 3 &

A kneaded product was prepared in the same manner as in Example 1, except that an ethylene-methacrylic acid copolymer having a density of 0.93 and a melting temperature of 110 ° C was used instead of the ultra low density polyethylene (VLDPE) as a polymer additive in Example 1 .

&Lt; Comparative Example 4 &

A kneaded product was prepared in the same manner as in Example 6, except that 400 g of ultra low density polyethylene (VLDPE) was used in Example 6.

&Lt; Comparative Example 5 &

A kneaded product was prepared in the same manner as in Example 6, except that 20 g of ultra low density polyethylene (VLDPE) was used in Example 6. [

<Experimental Example 1>

The kneaded products prepared in Examples 1 to 7 and Comparative Examples 1 to 5 were charged into a test mold (MQFP 28 x 28) and cured at 180 kg / cm ² at 450 kg / cm ² for 180 seconds, Was performed 30 times.

The number of times the non-fill phenomenon occurred in the release operation was measured, and the results are shown in Table 1 below.

<Experimental Example 2>

The kneaded products prepared in Examples 1 to 7 and Comparative Examples 1 to 5 were charged into a test mold (MQFP 28 x 28) and cured at 180 kg / cm ² at 450 kg / cm ² for 180 seconds, Was performed 30 times.

The number of times that the demolding did not occur during the mold releasing operation was measured, and the results are shown in Table 2 below.

Referring to Tables 1 and 2, it can be confirmed from the results of the experiment using Comparative Examples 2 and 3 that the use of an additive having a melting temperature higher than 100 ° C makes it impossible to produce a release rubber.

In addition, in Examples 1 to 7, the filling property and the de-molding were remarkably improved as compared with Comparative Example 1 in which the polymer additive was not used.

Further, in Comparative Example 4, which does not satisfy the content range of the present invention, it is difficult to produce a product due to insufficient releasability, and in the case of Comparative Example 5, the filling property and deformation are somewhat improved It can be confirmed that the filling property and the deformation are significantly lower than those of Examples 1 to 7.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (12)

As a release-type rubber composition for improving releasability of a molding die,
, 60 to 100 parts by weight of butadiene rubber (BR), 0 to 40 parts by weight of ethylene-propylene diene monomer rubber (EPDM) and 5 to 40 parts by weight of a polymer additive having a melting temperature (Tm) Rubber; And
5 to 60 parts by weight of a wax, 0.5 to 10 parts by weight of a curing agent and 5 to 110 parts by weight of an inorganic filler and an adsorbent based on 100 parts by weight of the uncrosslinked rubber;
Wherein the rubber composition comprises a polyolefin. The releasing rubber composition according to claim 1, wherein the uncrosslinked rubber contains 10 to 30 parts by weight of a polymer additive. delete The polymer additive according to claim 1, wherein the polymer additive is at least one selected from the group consisting of a polyolefin-based elastomer, a copolymer composed of a monomer for polyolefin and an acrylic acid monomer, an ionomer thereof or a copolymer composed of a monomer for polyolefin and an acrylate monomer copolymer. &lt; / RTI &gt; 5. The polyolefinic elastomer of claim 4, wherein the polyolefinic elastomer is selected from the group consisting of ultra low density polyethylene (VLDPE); Polybutene; Poly-4-methyl-1-pentene (TPX); Copolymers of propylene, butene, hexene and / or octene with ethylene; And an olefinic thermoplastic elastomer. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; 5. The method of claim 4, wherein the copolymer is selected from the group consisting of ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ionomer of ethylene- methacrylic acid copolymer, ethylene-methacrylic acid copolymer EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-alkyl acrylate-acrylic acid copolymer, ethylene-alkyl methacrylate-methacrylic acid copolymer, ethylene-butyl acrylate copolymer (EBA) Acetate copolymer (EVA). &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The copolymer according to claim 4, wherein the copolymer is obtained by reacting 60 to 96% by weight of a monomer for polyolefin and 4 to 40% by weight of acrylic acid or an acrylate or vinyl acetate monomer based on 100% by weight of the copolymer Lt; / RTI &gt; The releasing rubber composition according to claim 1, wherein the polymer additive is an ethylene-propylene copolymer or an ethylene-butylene copolymer. The releasing rubber composition according to claim 1, wherein the wax is a mixture of polyethylene having a weight average molecular weight of 200 to 3000 and slip agent. The release-type rubber composition according to claim 1, wherein the curing agent is an organic peroxide. The release rubber composition according to claim 1, wherein the inorganic filler is one or a mixture of two or more selected from the group consisting of silica, talc, alumina, potassium carbonate, calcium carbonate, aluminum hydroxide, titanium oxide and carbon black. A mold releasing rubber sheet produced by the release rubber composition according to claim 1.

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