KR100954767B1 - Compositions for Silicone Rubber Blanket and Silicone Rubber Blanket for Micropatterning in Offset Printing Prepared Using Same - Google Patents

Abstract

The present invention relates to a silicone blanket rubber composition and a silicone rubber blanket for micro pattern offset printing prepared using the same, more specifically 5 to 50% by weight of high vinyl polysiloxane, based on the total weight of the composition; 35-80 wt% low vinyl polysiloxane; 5 to 15 weight percent polysiloxane hydride; 10-50 ppm by weight of platinum catalyst; And 0.5 to 2% by weight of an anti-polymerizing agent, and a silicone blanket rubber composition for micro-pattern offset printing having excellent swelling properties and releasability.

Description

Compositions for Silicone Rubber Blanket and Silicone Rubber Blanket for Micropatterning in Offset Printing Prepared Using Same

The present invention relates to a silicone blanket rubber composition and a silicone rubber blanket for micro pattern offset printing produced thereby.

In general, offset printing is a method in which a paint image is transferred to a surface of a blanket rubber sheet on a pattern roll or plate, and the paint image of the blanket is transferred to a print object and printed indirectly. Therefore, in the offset printing plate, the image is the same as the original, the image of the blanket is the reverse, and on the print object, it appears the same as the original. At this time, since the paint on the pattern roll or the plate is first transferred to the blanket when printing with an offset press, the paint is called off and the paint on the blanket is buried again on the printing object.

Here, when the paint is on the blanket, a small amount of solvent in the paint penetrates into the blanket rubber plate, which swells the blanket rubber plate. As the number of prints increases, the swelling of the blanket rubber sheet gradually progresses, and when the paint buried in the blanket does not progress in three steps, the swelling of the blanket rubber sheet gradually progresses.

Rubber blankets for offset printing use a variety of synthetic rubbers, typically styrene butadiene rubber, acrylonitrile butadiene rubber, butyl rubber, ethylene-propylene diene rubber, polybutadiene rubber, polychloroprene rubber, polyisoprene rubber, and silicone rubber. Etc. can be mentioned. However, when printing with the rubber blanket used for such conventional offset printing, the print quality was not good and the micro-pattern could not be printed under various conditions.

Accordingly, the present invention provides a silicone blanket rubber composition suitable for extending the life of the blanket for offset printing and excellent micro-pattern printing and excellent swelling characteristics with excellent printing properties and mold release properties, and a silicone rubber for offset printing micro-patterns produced thereby. It is an object to provide a blanket.

In order to achieve the above object, the present invention provides a silicone blanket rubber composition comprising a vinyl polysiloxane, polysiloxane hydride, a platinum catalyst and a polymerization inhibitor.

In addition, the present invention provides a silicone rubber blanket for micro pattern offset printing prepared by heat curing or UV curing the silicone blanket rubber composition.

The silicone rubber blanket according to the present invention is not only excellent in the degree of curing and printing properties, but also excellent in releasability as the swelling property and the restoring force are maximized, so that the silicone rubber blanket can be applied to offset printing requiring a fine pattern of fineness. The life can be prolonged dramatically. If the silicone rubber blanket with excellent release property and maximum life span is applied to the photolithography process requiring a fine pattern, the photoresist wasted in the photolithography process can be efficiently reused, thereby reducing the production time. Cost can be reduced by omitting and drying equipment, which can dramatically improve productivity.

The silicone blanket rubber composition in the present invention is basically a high vinyl polysiloxane having a vinyl group content of 0.1 to 0.4 mmole / g; Low vinyl polysiloxanes having a vinyl group content of 0.01 to 0.1 mmole / g; Polysiloxane hydrides; Platinum catalysts; And anti-polymerization agents. Optionally, a diluent for viscosity control of the composition; And / or a silicone gum polymer for imparting functionality to the above composition.

Hereinafter, the composition of the present invention will be described in detail for each component. Viscosity values in the present invention are made at 25 ° C., which is a typical measurement condition in the art, unless otherwise specified.

(One) High vinyl Polysiloxane

In the vinyl polysiloxane of the present invention, the viscosity of the high vinyl polysiloxane containing relatively many vinyl groups is about 200 to 1,000 cPs as measured by Brookfield viscometer at 25 ° C., and the high vinyl polysiloxane is represented by R ¹ in Formula 1 For example, a compound containing one or two vinyl groups, preferably having a vinyl group content of about 0.1 to 0.4 mmole / g.

R ¹ _a SiO _{(4-a) / 2}

Wherein R ¹ is an alkenyl group (eg, C ₂ -C ₁₀ ) and a is a positive number from about 1.9 to 2.05.

The high vinyl polysiloxane is preferably included in an amount in the range of about 5 to 50% by weight, based on the total weight of the composition, wherein the content is less than 5% by weight, the silicone rubber may become hard, and 50% by weight If exceeded, the formed silicone rubber can be easily broken.

(2) Low vinyl Polysiloxane

The viscosity of the low vinyl polysiloxane containing relatively few vinyl groups in the vinyl polysiloxane of the present invention is about 1,000 to 200,000 cPs as measured by Brookfield viscometer at 25 ° C., and the low vinyl polysiloxane is represented by R ² in For example, a compound containing two or four vinyl groups, and the low vinyl polysiloxane preferably has a vinyl group content of about 0.01 to 0.1 mmole / g.

R ² _b SiO _{(8-b) / 2}

Wherein R ² is an alkenyl group (eg C ₂ -C ₁₀ ) and b is a positive number from about 1.2 to 4.8.

The low vinyl polysiloxane is preferably included in an amount in the range of about 35 to 80% by weight based on the total weight of the composition, where the content is less than 35% by weight, the tensile strength of the silicone rubber may be weakened, 80% by weight If it exceeds the high viscosity it is difficult to produce a silicone rubber sheet.

(3) Polysiloxane Hydride

Polysiloxane hydride is a compound in the composition of the present invention that acts as a binder, a compound containing, for example, one or two hydride groups at both terminal portions of the polysiloxane, the activation proceeds by a catalyst, the vinyl polysiloxane The π bond of is made unstable to combine.

R ³ _c SiO _{(4-c) / 2}

Wherein R ³ is a C ₁ -C ₁₀ alkyl group at both terminal sites, for example with one or two hydride groups, c is a positive number from about 1.9 to 2.05.

The weight average molecular weight of the polysiloxane is preferably in the range of about 3,000 to 10,000. The polysiloxane hydride polymer is preferably included in an amount in the range of about 5 to 15% by weight, based on the total weight of the silicone blanket rubber composition of the present invention. Or surface stickiness occurs, and if it exceeds 15% by weight, the length of the crosslinked polymer chain is short and the physical properties are degraded. For the same reason, the vinyl group and hydride ratios are preferably set between about 1 and 4 times in the number ratio.

(4) platinum catalyst

To the silicone blanket rubber composition of the present invention, a platinum catalyst may be added in powder form to activate the reaction. The amount of the platinum catalyst added is preferably in the range of about 10 to 50 ppm by weight based on the total weight of the composition. If the content is less than 10 ppm by weight, the curing may not proceed well at a high temperature. Curing may proceed.

(5) polymerization inhibitor

In accordance with the present invention, it is preferred that the silicone blanket rubber composition containing the platinum catalyst contains an polymerization inhibitor. This is because curing of the composition can proceed rapidly at room temperature due to the excellent reactivity of the added platinum catalyst. The polymerization inhibitor to be used may be any conventionally used in the art, and specific examples thereof include phosphoric acid, formic acid and methane sulfonic acid; Methanol, 2,6-di- t -butyl-4-methyl-phenol and the like, but are not limited to these.

The addition amount of the polymerization inhibitor is preferably in the range of about 0.5 to 2% by weight based on the total weight of the composition, if the content exceeds 2% by weight may not proceed at high temperatures.

(6) silicone gum ( gum )

Optionally, a silicone gum is added to impart functionality to the silicone rubber blanket of the present invention, wherein a high molecular weight polysiloxane compound having a viscosity of about 1,000 to 5,000,000 cPs as measured by a Brookfield viscometer at 25 ° C. is used. Since the silicone gum itself has no tensile strength or tear strength at all, and does not cause any reaction by itself, it is produced by adding a catalyst and a curing agent to this and then curing it at a high temperature. For example, silicon gums are prepared by heating to high temperatures in the presence of cyclic catalysts. At this time, by changing the organic group in the siloxane side chain can be made a silicon gum having a variety of different properties. Silicone gums may be classified by organic groups attached to the siloxane side chains, which may include methyl groups, vinyl groups, phenyl groups, fluoro groups, acrylic groups, urethane groups, and the like. ASTM also classifies silicone gums as having methyl groups, including molding, cryogenic, low comprssion sets, high tearing, high tensile, oil resistant, and food.

The addition amount of the silicone gum is preferably in the range of about 1 to 5% by weight based on the total weight of the composition of the present invention. When the content exceeds 5% by weight, the viscosity increases, which makes it difficult to prepare a silicone rubber blanket.

(7) thinner

Optionally, small amounts of organic solvent may be added to effectively control the viscosity of the silicone blanket rubber in the present invention. Preferably, toluene, xylene, normal hexane, hexane, methyl ethyl ketone, ethyl acetate, ethanol, methanol, butyl acetate, and the like can be cited. ° C) or xylene (140 ° C) may be suitably used.

The amount of diluent added may vary depending on the viscosity desired in the composition of the present invention and the type of organic solvent used, which can be readily determined during the process by those skilled in the art.

The silicone blanket rubber composition containing the above components may be prepared in the form of a bulk molding compound (BMC) form or a sheet molding compound (SMC) form.

BMC form is mixed with the composition to form a dough-like state to be injected into the mold or located on the lower side of the inside of the mold during compression molding, for example at a temperature of 50 to 160 ℃ / 50 kg / ㎠ It is pressurized for a certain time according to the target thickness by pressure and heat cured or UV cured to produce a thermosetting synthetic resin molded article of a desired shape, that is, a silicone rubber blanket.

SMC form is prepared by mixing and stirring the composition and then packaging with a protective film for aging for a certain time (aging). Since the SMC form has a high viscosity due to the injected silicone gum to form a solid sheet form, the protective film is removed into a suitable size after removal of the protective film. A thermosetting synthetic resin molded article of a desired shape, ie, silicone rubber, is pressed into a mold into which an SMC form is injected, for example, at a temperature of 50 to 160 ° C. at a pressure of 50 to 160 kg / cm 2 for a predetermined time, and thermally cured or UV cured. It will be produced as a blanket.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. However, these examples are only for illustrating the present invention, the contents of the present invention is not limited or limited thereto.

Example  1-1 to 1-4: Preparation of Liquid Silicone Rubber Composition

Various liquid silicone rubber compositions were prepared as shown in Table 1 below.

High-vinyl polysiloxane and low-vinyl polysiloxane were added to a 250 ml container, followed by stirring at 2000 rpm in a stirrer Dispermat for about 10 minutes. Polysiloxane hydride was added thereto, a polymerization inhibitor was added thereto, followed by stirring at 2000 rpm for about 10 minutes. Subsequently, a platinum catalyst was added thereto, mixed for 5 minutes in an ARE-250 mixer, and degassed for 5 minutes to prepare a liquid silicone rubber composition.

Example  2-1 to 2-3: Preparation of solvent type high viscosity liquid silicone rubber composition

Various liquid silicone rubber compositions were prepared as shown in Table 2 below.

High-vinyl polysiloxane and low-vinyl polysiloxane were added to a 250 ml container, followed by stirring for about 10 minutes at 2000 rpm in a stirrer Dispermat. Polysiloxane hydride was added thereto, a polymerization inhibitor was added thereto, followed by stirring at 2000 rpm for about 10 minutes. Subsequently, xylene, toluene or normal hexane was added thereto, followed by stirring at 2000 rpm for about 10 minutes. A platinum catalyst was added thereto, mixed for 5 minutes in an ARE-250 mixer, and degassed for 5 minutes to prepare a high viscosity liquid silicone rubber composition of a solvent type.

Example  3-1 to 3-3: Preparation of Liquid Silicone Rubber Composition Added with Silicone Gum

Various liquid silicone rubber compositions were prepared as shown in Table 3 below.

High-vinyl polysiloxane and low-vinyl polysiloxane were added to a 250 ml container, followed by stirring at 2000 rpm for about 10 minutes in a stirrer dispermat. Polysiloxane hydride was added thereto, a polymerization inhibitor was added thereto, followed by stirring at 2000 rpm for about 10 minutes. Subsequently, a silicon gum containing a phenyl group was added thereto, followed by stirring at 2000 rpm for about 10 minutes. A platinum catalyst was added thereto, mixed for 5 minutes in an ARE-250 mixer and degassed for 5 minutes to prepare a liquid silicone rubber composition to which silicone gum was added.

<Evaluation>

1. Evaluation of swelling properties for solvents (%)

The silicone blanket rubber cured to a thickness of 500 μm was cut into a size of 10 cm × 10 cm, and the high boiling point solvent BC (butyl cellusolve) was contacted for 30 minutes, and then the swelling characteristics were evaluated through weight change.

2. Physical properties (tensile strength: Kgf / Mm2)

The tensile strength of the silicone blanket rubber cured to a thickness of 500 μm was cut into 1 cm using an Instron 4443 model and a universal testing machine (UTM).

3. Evaluation of printing frequency and swelling characteristics (%)

A screen printing plate is used to transfer the ink, which is generally used, to a silicon blanket rubber cured to a thickness of 500 µm, and then left for 1 minute to peel off the ink using a scotch tape. After the simple printing was performed 60 times, the swelling characteristics were evaluated through weight change.

Test Example  1: liquid silicone Blanket  Rubber

The liquid silicone rubber composition prepared in Example 1 was coated on one side of a polyethylene (PET) film with an applicator (applicator) to a thickness of 500 μm and then degassed in a convection oven at 70 ° C. for 10 minutes. Cured for 20 minutes in a 150 ° C convection oven. The evaluation test described above was performed on the obtained specimens, and the results are shown in Table 4 and FIG. 2.

Test Example  2: solvent type high viscosity liquid silicone Blanket  Rubber

The physical properties of the liquid silicone blanket rubber composition prepared in Example 2 were evaluated in the same manner as in Test Example 1. These results are shown in Table 5 below.

Test Example  3: liquid silicone with silicone gum added Blanket  Rubber

The physical properties of the liquid silicone blanket rubber composition prepared in Example 3 were evaluated in the same manner as in Test Example 1. These results are shown in Table 6 and FIG. 2.

Test Example  4: formation of fine patterns

Using the blanket rubber according to Example 1-1 cured in the same manner as in Test Example 1, offset printing was performed to form a fine pattern on printing paper. The results are shown in FIG.

From the results of these test examples 1 to 4 and Figs. 1 and 2, the silicone blanket rubber of the present invention has excellent printing properties and releasability to efficiently form fine fine patterns of 84.26 μm and 85.78 μm in width, respectively. It can be seen that when the content of the silicone polymer is high or additionally the silicone gum is added, the swelling is further increased, so that the printing property can be further improved and the life of the silicone blanket rubber is increased.

1 is a view showing a fine pattern of the black strip offset printing using a silicon blanket rubber according to an embodiment of the present invention,

2 is a graph showing print swelling characteristics after performing offset printing using a silicon blanket rubber according to an embodiment of the present invention.

Claims (9)

Based on the total weight of the composition, 5 to 50% by weight of a high vinyl polysiloxane having a vinyl group content of the following Formula 1 at 0.1 to 0.4 mmole / g; 35 to 80 wt% of a low vinyl polysiloxane having a vinyl group content of the following Formula 2, 0.01 to 0.1 mmole / g; 5 to 15% by weight of polysiloxane hydride of Formula 3; 10-50 ppm by weight of platinum catalyst; And 0.5 to 2 wt% of polymerization inhibitor Including, A silicone blanket rubber composition for micropattern offset printing, further comprising 1 to 5% by weight of a silicone gum based on the total weight of the composition: [Formula 1] R ¹ _a SiO _{(4-a) / 2} [Formula 2] R ² _b SiO _{(8-b) / 2} [Formula 3] R ³ _c SiO _{(4-c) / 2} In Formula 1, R ¹ is an alkenyl group, a is a positive number of 1.9 to 2.05; In Formula 2, R ² is an alkenyl group, b is a positive number of 1.2 to 4.8; In Formula 3, R ³ is a C ₁ -C ₁₀ alkyl group having a hydride group at both terminal sites, c is a positive number of 1.9 to 2.05. Based on the total weight of the composition, 5 to 50% by weight of a high vinyl polysiloxane having a vinyl group content of the following Formula 1 at 0.1 to 0.4 mmole / g; 35 to 80 wt% of a low vinyl polysiloxane having a vinyl group content of the following Formula 2, 0.01 to 0.1 mmole / g; 5 to 15% by weight of polysiloxane hydride of Formula 3; 10-50 ppm by weight of platinum catalyst; And 0.5 to 2 wt% of polymerization inhibitor Including, The viscosity of the high vinyl polysiloxane is 200 to 1,000 cPs at 25 ℃, the viscosity of the low vinyl polysiloxane is 1,000 to 200,000 cPs at 25 ℃, the silicone blanket rubber composition for micro pattern offset printing. [Formula 1] R ¹ _a SiO _{(4-a) / 2} [Formula 2] R ² _b SiO _{(8-b) / 2} [Formula 3] R ³ _c SiO _{(4-c) / 2} In Formula 1, R ¹ is an alkenyl group, a is a positive number of 1.9 to 2.05; In Formula 2, R ² is an alkenyl group, b is a positive number of 1.2 to 4.8; In Formula 3, R ³ is a C ₁ -C ₁₀ alkyl group having a hydride group at both terminal sites, c is a positive number of 1.9 to 2.05. The method of claim 1, A silicone blanket rubber composition for micro pattern offset printing, wherein the polysiloxane hydride has a weight average molecular weight of 3,000 to 10,000. The method of claim 1, A silicone blanket rubber composition for micro pattern offset printing, further comprising a diluent. Based on the total weight of the composition, 5 to 50% by weight of a high vinyl polysiloxane having a vinyl group content of the following Formula 1 at 0.1 to 0.4 mmole / g; 35 to 80 wt% of a low vinyl polysiloxane having a vinyl group content of the following Formula 2, 0.01 to 0.1 mmole / g; 5 to 15% by weight of polysiloxane hydride of Formula 3; 10-50 ppm by weight of platinum catalyst; And 0.5 to 2 wt% of polymerization inhibitor Including, The silicone blanket rubber composition for micro-pattern offset printing, in which the hydride groups to vinyl groups are contained in a number ratio of 1 to 4 times in the silicone blanket rubber composition. [Formula 1] R ¹ _a SiO _{(4-a) / 2} [Formula 2] R ² _b SiO _{(8-b) / 2} [Formula 3] R ³ _c SiO _{(4-c) / 2} In Formula 1, R ¹ is an alkenyl group, a is a positive number of 1.9 to 2.05; In Formula 2, R ² is an alkenyl group, b is a positive number of 1.2 to 4.8; In Formula 3, R ³ is a C ₁ -C ₁₀ alkyl group having a hydride group at both terminal sites, c is a positive number of 1.9 to 2.05. The method of claim 1, The silicone blanket rubber composition for micropattern offset printing whose silicone gum contains a methyl group, a vinyl group, a phenyl group, a fluoro group, an acryl group, or a urethane group. The method of claim 1, A silicone blanket rubber composition for micro pattern offset printing, wherein the viscosity of the silicone gum is 1,000 to 5,000,000 cPs at 25 ° C. The method of claim 4, wherein A silicone blanket rubber composition for micro pattern offset printing, wherein the diluent is toluene, xylene, normal hexane, hexane, methyl ethyl ketone, ethyl acetate, methanol, ethanol, butyl acetate, or a mixed solvent thereof. The silicone rubber blanket for micropattern offset printing obtained by heat-hardening or UV-curing the composition of any one of Claims 1-8.

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