KR101425365B1 - Silicone rubber clay composition - Google Patents

Abstract

The present invention relates to a silicone rubber clay composition and, more particularly, to a silicone rubber clay composition that has a proper strength (softness) in an uncured state to facilitate shape change and is capable of showing an excellent appearance in a cured state. According to the present invention, there is provided a silicone rubber clay composition that has a proper softness in an uncured compound state to facilitate shape change. According to the present invention, silica with a particle size of 7 to 50 nm and a specific surface area (BET value) of 50 to 300 m2/g is applied as a filling agent, and thus the silicone rubber clay strength can be controlled and problems of existing clay associated with easy form collapse can be improved. Also, a plasticizer that has a viscosity of 200 centipoise or less at 25°C is applied, and thus a plasticity increment can be controlled. Accordingly, the present invention can be reused in a non-hardened state over a long period of time and a solidification problem of existing clay can be improved. Also, the silicone rubber clay composition according to the present invention generates few surface bubbles in a cured state, and thus is capable of showing an excellent appearance.

Description

SILICONE RUBBER CLAY COMPOSITION [0001]

More particularly, the present invention relates to a silicone rubber clay composition which has an appropriate strength (tear) in an uncured state and is easy to change in shape and can exhibit an excellent appearance in a cured state.

Clay is a persistent, dusty soil, commonly known as a material used in art education. Recently, it has been reported that stereolithography using clay helps improve children 's creativity and space ability, and the interest of the material and its educational value of clay is increasing. However, generally used clay has a merit that it is easy to use because it is easily kneaded, but it may cause stickiness due to a lot of moisture and may cause a bad feeling to feel in the hand to be bad. Further, when the film is left at room temperature for a certain period of time, moisture is evaporated and hardened, which makes it difficult to reuse. Therefore, there is a need for research on a clay composition which can be easily re-shaped while having a proper size and can be reused for a long time without being hardened.

In order to solve the above problems, there is provided a silicone rubber clay composition which has a moderate whiteness in an uncured state, is easily changed in shape, and can exhibit an excellent appearance in a cured state.

A silicone rubber clay composition according to one embodiment of the invention comprises the following components:

(a) 100 parts by weight of a silicone raw material having a repeating unit represented by the following formula (1) and having a viscosity of 10,000,000 centipoise or more at 25 캜;

(b) 15 to 40 parts by weight of silica having a particle size in the range of 7 to 50 nanometers and a specific surface area (BET value) of 50 to 300 m ² / g;

(c) 0.3 to 10 parts by weight of a plasticizer having a viscosity of 200 centipoise or less at 25 占 폚;

(d) 0.01 to 2 parts by weight of platinum complex compound;

(e) 0.3 to 3 parts by weight of a crosslinking agent; And

(f) 0.01 to 1 part by weight of a hardening retarder.

[Chemical Formula 1]

In Formula 1,

R is an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, an aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms, or an aromatic unsaturated hydrocarbon group having 6 to 30 carbon atoms, and a is 1.90 to 2.05.

Hereinafter, each component contained in the silicone rubber clay composition will be described in detail.

Silicon raw material

The silicon raw material used as the raw material resin in the silicone rubber clay composition of the present invention has a repeating unit represented by the above formula (1). In Formula 1, R may be a methyl group, a vinyl group, or a phenyl group. More preferably at least one functional group selected from the group consisting of a methyl group, a vinyl group and a phenyl group in a side chain, and at least one group selected from the group consisting of an aliphatic saturated hydrocarbon group, an aliphatic unsaturated hydrocarbon group and an aromatic unsaturated hydrocarbon group May be a linear organopolysiloxane.

The silicone raw material may preferably be a linear organopolysiloxane having a molecular weight of 400,000 to 700,000 and a viscosity of 10,000,000 centipoise or more at 25 DEG C and a high polymerization degree of 2,000 to 10,000 siloxane units. When using a raw material having a viscosity of 10,000,000 centipoise or more, easy workability can be secured in toning milling.

The content of the total vinyl groups in the silicon raw material is preferably 0.01 to 10 mol%, more preferably 0.04 to 1 mol%. If the content of the vinyl group is less than 0.01 mol%, the curing rate is too slow, and bubbles are generated in the outer appearance after the curing operation to form an unsatisfactory appearance. If the content is more than 10 mol%, the curing rate becomes slow due to the steric hindrance effect, Results can be shown.

Silica ( Reinforcement  Filler)

The silica is used as a reinforcing filler. When used as a reinforcing filler, amorphous synthetic dry silicas are preferred. It is particularly preferable that the silica has a particle size in the range of 7 to 50 nanometers and a minimum specific surface area (BET value) of 50 to 300 m ² / g. If the particle size and the minimum specific surface area are out of the above range, the resultant product may be poor in hardness, inadequate degree of hardness, and inferior in appearance.

As the silica, general dry silica not subjected to a surface treatment or dry silica subjected to a surface treatment can be used. However, when wet silica is used, a large amount of moisture (4 to 7%) may cause bubble defects in the appearance of the molded product during curing.

The content of the silica may be 15 to 40 parts by weight, preferably 15 to 35 parts by weight, based on 100 parts by weight of the silicone raw material. If the amount is less than 15 parts by weight, it is difficult to maintain the shape of the clay for a predetermined time, and if it exceeds 40 parts by weight, the rubber clay becomes too hard and it may be difficult for children to knead.

Plasticizer

The plasticizer enhances the dispersibility of the silica as a reinforcing filler, so that uniformity and adequate strength (tearing) can be obtained, thereby preventing occurrence of creep hardening. Therefore, it can be used for the purpose of increasing strength (tearing) and storage period.

The plasticizer preferably has a viscosity of less than 200 centipoise at 25 DEG C, and when the viscosity of the plasticizer is more than 200 centipoise, the silica surface treatment effect may be deteriorated, which may adversely affect the control of tackiness and storage stability.

In the silicone rubber clay composition, the content of the plasticizer may be 0.3 to 10 parts by weight, and more preferably 0.5 to 7 parts by weight, based on 100 parts by weight of the silicon raw material. If the amount is less than 0.3 part by weight, the elasticity of the viscoelasticity is strong, so that the rubber clay may be shrunk after being formed into a certain shape, and if it is more than 10 parts by weight, the shape may be collapsed .

The plasticizer may be a compound represented by the following general formula (2).

(2)

In Formula 2,

R1 is a hydroxyl group, an alkoxy group or an amino group,

R2 is an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, an aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms, or an aromatic unsaturated hydrocarbon group having 6 to 30 carbon atoms,

m and n are integers between 2 and 30, respectively.

The plasticizer may be a low viscosity silicone polymer having a hydroxyl group, an alkoxy group or an amino group at both terminals, more preferably a hydroxyl group at both terminals, May be a low-viscosity silicone polymer having a methylvinyl functional group.

The plasticizer used in one embodiment of the present invention is a plasticizer that occurs over time when the silica is directly bonded to the silicon raw material by forming a hydrogen bond with the silica, It can suppress the cracking phenomenon. As a result, the increase in plasticity with time can be minimized. Also, the vinyl functional groups present in the side chain can participate in the crosslinking to form a fast curing system and can remarkably suppress the phenomenon of bubbling on the surface after curing.

platinum Complex  The compound (curing catalyst)

The platinum complex compound may be used as a curing catalyst. The platinum complex compound preferably has a zero oxidation number and forms a complex with a vinylsiloxane having a low molecular weight (see general formula 1 below). To increase the reactivity and compatibility with the silicone polymer. The platinum content in the platinum complex compound may be from 0.5% to 6%.

[Formula 1]

In the silicone rubber clay composition, the amount of the platinum complex compound to be used may be 0.01 to 2.0 parts by weight, more preferably 0.01 to 1 part by weight based on 100 parts by weight of the silicon raw material. If the amount of the platinum complex compound is less than 0.01 part by weight, unfavorable curing may occur or the curing rate may become too slow, resulting in defective appearance due to the formation of bubbles on the surface of the product. If the curing catalyst content is more than 2.0 parts by weight, Resulting in poor storage stability.

Cross-linking agent

In the production of the silicone rubber clay composition, the curing method is an additive method, and the crosslinking agent is used for curing the silicone rubber. In the silicone rubber clay composition, the content of the crosslinking agent may be 0.3 to 3 parts by weight, and more preferably 0.5 to 1.5 parts by weight, based on 100 parts by weight of the silicone rubber. If it is used in an amount less than 0.3 parts by weight, bubbles may be generated on the surface after curing due to uncured or slow curing rate, resulting in poor appearance. When the amount is more than 3 parts by weight, storage stability may be poor and rapid solidification may occur.

The crosslinking agent may be a hydrogen silicone polymer represented by the following formula (3).

(3)

In Formula 3,

n is an integer of 5 to 30, and m is an integer of 0 to 30.

The hydrogen silicone polymer includes a siloxane group containing SiH, and the hydrogen (H) of the SiH bonds with a vinyl group present in the silicon raw material to form a crosslink.

Hardening Retarder

When a platinum complex compound is used as a curing catalyst in the production of a silicone rubber clay composition, a curing retardant may be used to inhibit the catalytic activity of the platinum complex compound. The curing retarder may be used in an amount of 0.01 to 1 part by weight, and more preferably 0.03 to 0.5 part by weight based on 100 parts by weight of the silicone raw material. If the amount is less than 0.01 part by weight, it is difficult to effectively serve as a retarding agent, and the solidification phenomenon may occur quickly. If the amount is more than 1 part by weight, the curing rate may become too slow and the surface may become uncured or bubbles may appear on the surface after curing.

The curing retarder may be selected from the group consisting of tris (2,4-di-tert-butylphenyl) phosphite [(2,4- (t-Bu) ₂ C ₆ H ₃ O) ₃ P] cycloalkyl when hexanol [C ₈ H ₁₂ O], and triallyl iso may include one or more selected from the group consisting of isocyanurate _{[C 12 H 15 N 3 O} 3]. More preferably, tris (2,4-di-tert-butylphenyl) phosphite [(2,4- (t-Bu) ₂ C ₆ H ₃ O) ₃ P] can be used as a curing retarder (See Formula 2). The tris (2,4-di-tertiary-butylphenyl) phosphite exhibits remarkably effective storage stability even at a small usage amount different from conventional retarders and can remarkably suppress the generation of bubbles after curing.

[Formula 2]

The curing method of the silicone rubber clay composition according to one embodiment of the present invention may be a addition type curing method and the platinum complex compound (curing catalyst), the crosslinking agent and the curing retardant may form a curing mechanism.

The silicone rubber clay composition according to one embodiment of the present invention may further contain conventional additives as needed in addition to the above-described components, within the range not impairing the object of the present invention.

According to the present invention, it is possible to provide a silicone rubber clay composition having an appropriate strength (unfavorable) in an uncured compound state and being easily changeable in shape. According to the present invention, it is possible to control the strength of the silicone rubber clay by applying silica having a particle size of 7 to 50 nanometers and a specific surface area (BET value) of 50 to 300 m ² / g as a filler, The problem of clay can be improved. Further, by applying a plasticizer having a viscosity of 200 centipoise or less at 25 캜, it is possible to control the increase of plasticity, and it can be reused in a state where it is not hardened for a long time and the solidification phenomenon which is a problem of existing clay can be improved. In addition, the silicone rubber clay composition according to the present invention hardly generates bubbles on the surface in a cured state, and can exhibit excellent appearance.

The silicone rubber clay composition according to the present invention can be used for stereolithography activities of children and adults.

Hereinafter, the present invention will be described in more detail with reference to Examples. The objects, features and advantages of the present invention will be readily understood by the following examples. The present invention is not limited to the embodiments described herein but may be embodied in other forms. The embodiments disclosed herein are provided so that the disclosure may be thorough and complete, and that those skilled in the art will be able to convey the spirit of the invention to those skilled in the art. Therefore, the present invention should not be limited by the following examples.

Examples 1 to 2

Preparation of silicone rubber clay composition

Silica (reinforcing filler) and a plasticizer were added to the kneader (Hermann Linden, LK Ⅲ 2) as an additive three times in an amount of three times, as shown in the composition shown in the following Table 1, to the silicon raw material having both side vinyl groups and methyl vinyl side chains A platinum complex compound (curing catalyst), a crosslinking agent and a curing retardant were added and dispersed at a room temperature by a simple mixing process to prepare a silicone rubber clay composition (Example 1). In order to increase the dispersing effect of the silica, the mixture is uniformly dispersed at a temperature of 80 ° C., and then heat-kneaded (aging step) is carried out 170 C for 3 hours, cooling and kneading were carried out at 80 DEG C for 3 hours, followed by removal of the compound sufficiently at room temperature for 2 days and aging. Thereafter, a platinum complex compound (curing catalyst) and a crosslinking agent A hardening retardant was added and dispersed to prepare a uniform silicone rubber clay composition (Example 2).

Comparative Examples 1 to 4

Silica (reinforcing filler) and a plasticizer were added in three times in a kneader (Hermann Linden, LK III2) as an additive to silicon raw materials and then subjected to a simple mixing process at room temperature to prepare platinum complex compounds (Curing catalyst), a crosslinking agent and a curing retardant were added and dispersed to prepare a silicone rubber clay composition (Comparative Examples 1 and 2). In addition, after the above simple mixing process, cooling and kneading were carried out at 80 ° C for 3 hours and then taken out for 2 hours to perform the heat-kneading for 3 hours at 170 ° C in order to increase the dispersing effect of silica. (Curing catalyst), a crosslinking agent and a curing retardant were added and dispersed by using a kneader or a twin-roll mill to prepare a silicone rubber clay composition (Comparative Examples 3 and 4).

Silicone rubber clay composition (unit: parts by weight) Example
One Example
2 Comparative Example
One Comparative Example
2 Comparative Example
3 Comparative Example
4 The vinyl group at the terminal end is methyl vinyl,
Silicon raw material (0.23 mol%) ^{1 )} 100 100 100 100 100 100 Dry silica (specific surface area 210 m ² / g) ²⁾ 32 45 32 32 Surface treated dry silica (specific surface area 120 m ² / g) ³⁾ 32 Wet silica (specific surface area 190 m ² / g) ⁴⁾ 32 Plasticizers (methyl oligomers with side chain hydroxyl groups, side chain methyl groups) ⁵⁾ 7 7 7 7 Plasticizers (methyl vinyl oligomers with hydroxyl group side-chain vinyl groups at both ends) ⁶⁾ 2.5 7 Platinum complex compound ⁷⁾ 0.25 0.25 0.25 0.25 0.25 0.25 Crosslinking agent ⁸⁾ One One One One One One Curing retarder (1-ethynyl-1-cyclohexanol) ⁹⁾ 0.5 0.5 0.5 0.5 Tris (2,4-di-tert-butylphenyl) phosphite] ¹⁰⁾ 0.1 0.1 Simple mixing (room temperature simple mixing) O O O Simple mixing (room temperature simple mixing) + heating and kneading (170 占 폚, 3 hours) O O O

1) Methylvinylsiloxane gum: SF3902M of KCC Co. Vinyl content 0.023 mol%

2) Dry silica: KCC D200 Specific surface area 210 m ² / g

3) Surface-treated dry silica: Tokuyama Co. REOLOSIL MT-10 Specific surface area 120 m ² / g

4) Wet silica: Tokuyama company Tokusil-USA Specific surface area 190 m ² / g

5) Plasticizer (methyl oligomer having hydroxyl group side chain methyl group at both ends): kcc SF2000E

6) Plasticizer (Methyl Vinyl Oligomer Having Hydroxyl Side-chain Vinyl Groups at Both Sides): Qidong Xin Jia Yuan Chemicals Co., Ltd JY-116-2

7) Platinum complex compound (curing catalyst): Shin-Tsu, PT-VTSC-1.0PS

8) Crosslinking agent: KCC SF6004P

8) Hardener (1-ethynyl-1-cyclohexanol): BASF Corporation 1-ETHYNYL-1-CYCLOHEXANOL

9) Hardening retarder [Tris (2,4-di-tert-butylphenyl) phosphite]: SONGNOX 1680 PX

Experimental Example

The silicone rubber clay compositions of the examples and comparative examples thus prepared were compared with each other according to the Williams type determination of plasticity according to the ASTM D926 standard. In addition, the uncured silicone rubber clay compositions prepared in the above Examples and Comparative Examples were made into a dice-shaped cube-shaped body and cured, and each of them was vulcanized in a general oven at 200 ° C for 10 minutes to cure the silicone rubber clay composition. The patterns were compared.

division Example
One Example
2 Comparative Example
One Comparative Example
2 Comparative Example
3 Comparative Example
4 Initial Gasso 145 152 336 267 145 150 One day past 155 158 373 335 150 156 3 days past 158 155 398 355 153 157 Five days past 158 159 425 369 155 159 Seven days past 160 163 449 386 157 164 15 days past 162 162 496 422 155 164 30 days past 167 165 553 485 159 167 Appearance after hardening Good Good Bad Bad Extremely
Bad Bad

Note) Plasticity: ASTM D926 According to Williams's plasticity measurement method

As shown in Table 2, the silicone rubber clay compositions according to Examples 1 and 2 have a moderate toughness in the uncured compound state and can easily change the shape, and the rate of change in plasticity with time is not high, It has the advantage that it can be reused in the state.

As a result of comparing appearance after curing in an oven, the silicone rubber clay compositions according to Examples 1 and 2 showed good appearance because bubbles were hardly generated on the surface, unlike Comparative Examples.

Claims (5)

A silicone rubber clay composition comprising:
(a) 100 parts by weight of a silicone raw material having a repeating unit represented by the following formula (1) and having a viscosity of 10,000,000 centipoise or more at 25 캜;
(b) 15 to 40 parts by weight of silica having a particle size in the range of 7 to 50 nanometers and a specific surface area (BET value) of 50 to 300 m ² / g;
(c) 0.3 to 10 parts by weight of a plasticizer represented by the following formula (2) and having a viscosity of 200 centipoise or less at 25 DEG C;
(d) 0.01 to 2 parts by weight of a platinum complex compound;
(e) 0.3 to 3 parts by weight of a crosslinking agent; And
(f) 0.01 to 1 part by weight of a hardening retarder.

[Chemical Formula 1]

In Formula 1,
R is an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, an aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms, or an aromatic unsaturated hydrocarbon group having 6 to 30 carbon atoms, and a is 1.90 to 2.05.

(2)

In Formula 2,
R1 is a hydroxyl group, an alkoxy group or an amino group,
R2 is an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, an aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms, or an aromatic unsaturated hydrocarbon group having 6 to 30 carbon atoms,
m and n are integers between 2 and 30, respectively.
The method according to claim 1,
The silicone rubber clay composition according to claim 1, wherein R is a methyl group, a vinyl group or a phenyl group.
delete A silicone rubber clay composition comprising:
(a) 100 parts by weight of a silicone raw material having a repeating unit represented by the following formula (1) and having a viscosity of 10,000,000 centipoise or more at 25 캜;
(b) 15 to 40 parts by weight of silica having a particle size in the range of 7 to 50 nanometers and a specific surface area (BET value) of 50 to 300 m ² / g;
(c) 0.3 to 10 parts by weight of a plasticizer having a viscosity of 200 centipoise or less at 25 占 폚;
(d) 0.01 to 2 parts by weight of a platinum complex compound;
(e) 0.3 to 3 parts by weight of a crosslinking agent represented by the following formula (3); And
(f) 0.01 to 1 part by weight of a hardening retarder.

[Chemical Formula 1]

In Formula 1,
R is an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, an aliphatic unsaturated hydrocarbon group having 2 to 10 carbon atoms, or an aromatic unsaturated hydrocarbon group having 6 to 30 carbon atoms, and a is 1.90 to 2.05.

(3)

In Formula 3,
n is an integer of 5 to 30, and m is an integer of 0 to 30.
The method according to claim 1,
Wherein the hardening retarder comprises at least one member selected from the group consisting of tris (2,4-di-tert-butylphenyl) phosphite, triallyl isocyanurate and 1-ethynyl-1-cyclohexanol ≪ / RTI >