JPH05179055A - Surface-modifying agent for polymer and surface-modified polymer - Google Patents

Abstract

PURPOSE:To provide the subject modifying agent composed of a specific fluorine compound, effective for exclusively lowering surface tension without lowering various physical properties of a polymer, having excellent compatibility and useful for the surface-printing layer of a printing offset blanket, etc. CONSTITUTION:The objective modifying agent is composed of a fluorine compound having (A) a surface-modifying part such as perfluoroalkyl group effective for lowering the surface tension of a polymer such as silicone rubber and acrylonitrilebutadiene copolymer rubber and (B) a reactive part with the polymer such as (meth)acryloyloxy group in the molecule. A surface-modified polymer can be produced by adding the modifying agent to the polymer at a ratio of 0.5-30phr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface modifier for a polymer and a surface-modified polymer, and more particularly to surface printing of a printing offset blanket suitable for printing fine patterns such as liquid crystal color filters. It relates to polymer surface modifiers and surface-modified polymers which are applied to the polymers used in the layer and reduce the surface tension of the polymers.

[0002]

Conventionally, intaglio offset printing and flat plate offset printing have been suitable for printing fine patterns. For example, three primary colors of red, green, and blue are formed in stripes on a glass substrate. It is also used when manufacturing color filters for liquid crystal color televisions arranged in a mosaic pattern.

In such offset printing, it is required to print a pattern accurately and without any defects. For that purpose, when the ink on the plate is transferred onto the offset blanket and then transferred to the glass substrate or the like, it is necessary that the ink on the blanket is transferred almost completely to the glass substrate or the like. In order to transfer the ink almost completely, it is necessary to use a material having a small surface tension, that is, a material that does not easily wet the ink, for the surface printing layer (surface rubber) of the offset blanket. Generally, there are the following methods for reducing the surface tension of a polymer. (a) Use polymers with low surface tension such as fluororubber and silicone rubber. (b) Coating with a polymer having a low surface tension such as fluororubber or silicone rubber. (c) A polymer such as fluororubber or silicone rubber having a small surface tension is blended during molding. (d) At the time of molding, a substance such as tetrafluoroethylene resin having a small surface tension is added.

By the way, if the surface tension is small, the transferability of the ink is improved, but if it is too small, the ink will not be transferred from the plate to the offset blanket. Therefore, in order to perform precision printing, it is necessary to use a blanket having an optimum surface tension for the equipment used for printing and printing conditions. For that purpose, it is necessary to finely control the surface tension of the polymer, but if the physical properties other than the surface tension of the polymer (normal physical properties, swelling, etc.) also change due to the control of the surface tension, the printing conditions will change. As a result, the optimum value of the surface tension also changes.

That is, in the above method (a), since the polymer itself constituting the surface printing layer is changed, other physical properties are significantly changed. Also in the case of (b) above, a special coating technique is required to prevent other physical properties from changing and peeling or the like from occurring. In the case of the above (c), a special blending technique is required due to the compatibility with the polymer, and the physical properties may change as the blending ratio changes. In the case of the above (d), there is a problem that the physical properties of the polymer are deteriorated when the mixed amount increases.

Therefore, an object of the present invention is to solve the above-mentioned technical problems, to minimize the influence on other physical properties, and to finely control the surface tension of the polymer, and a surface modifier for the polymer. It is to provide a polymer surface-modified with a modifier.

[0007]

Means and Actions for Solving the Problems The surface modifier for a polymer according to the present invention has in the molecule thereof a surface modification site for lowering the surface tension of the polymer and a site reactive with the polymer. It is characterized by comprising a fluorine compound. The surface-modified polymer of the present invention contains the surface-modifying agent in the amount of 0.5 to 30.
It is characterized by being mixed in a ratio of phr.

That is, the fluorine compound, which is the surface modifier of the present invention, has a surface modification site that lowers the surface tension of the polymer and a site reactive with the polymer in the molecule, and is compatible with each other. Since it is abundant, it can be mixed in the polymer at an arbitrary ratio, and the surface tension of the polymer can be lowered according to the mixing amount. Moreover, since the fluorine compound is chemically bonded to the polymer by the above reactive site, it has a characteristic that it does not change other physical properties of the polymer.

The surface tension of the polymer in the present invention means
It is a numerical value obtained from the contact angle of droplets formed by the solvent on the surface of the polymer, and the higher the contact angle, that is, the harder it is to wet, the lower the surface tension. Examples of the surface modification site of the fluorine compound in the present invention include a perfluoroalkyl group represented by the general formula: —C _n F _{2n + 1} (where n is an integer).

The reactive site of the fluorine compound in the present invention is, for example, a compound represented by the general formula: R ¹ R ² C = C (R ³ ) COO- (wherein R ¹ , R ² or R ³ are the same or And a hydrogen atom, a methyl group or an ethyl group). Specific examples include an acryloyloxy group and a methacryloyloxy group.

Specific examples of the fluorine compound in the present invention include a product name “Diefree FB-975”, which is a perfluoroalkyl acrylate manufactured by Daikin Industries, Ltd., and the like. Examples of the polymer in which the fluorine compound is mixed include, for example, silicone rubber and acrylonitrile-butadiene copolymer rubber (NBR) which have been conventionally used in the surface printing layer of an offset blanket, but are not limited thereto. Not a thing, but polyisoprene rubber (IR), ethylene-propylene copolymer (EPM, EPDM), chloroprene rubber (C
It is also applicable to polymers such as R), butadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber (IIR).

As the above-mentioned silicone rubber, various conventionally known silicone rubbers can be used. For example, a millable silicone rubber that can be kneaded, a room temperature vulcanizing (RTV) silicone rubber that cures at room temperature, Examples include injection-moldable LIM silicone rubber. The silicone rubber is polymethylsiloxane and the degree of polymerization is 100-8.
RTV silicone rubber based on liquid silicone gum with a low degree of polymerization of about 00 and degree of polymerization of 6000 to 10000
Millable silicone rubber based on a gel-like silicone gum of a certain degree is conceivable, but in each case, raw silica is an anhydrous silica-based reinforcing filler such as aerosil, talc,
It is supplied as a rubber compound containing an increasing filler such as mica and a dispersion accelerator. Generally, RTV silicone rubber is mostly polydimethylsiloxane, and as the millable silicone rubber, one in which a methyl vinyl group is introduced in an amount of about 0.1 to 0.5 mol% is used in order to balance crosslinkability and physical properties. There is. In addition, trifluoropropyl group-introduced FVMQ and phenyl group-introduced PVMQ
Etc. can also be used, and mixtures thereof can be used as well.

The amount of the fluorine compound mixed in the polymer is 0.5 to 30 phr with respect to the polymer. The polymer having such a fluorine compound mixed therein has a lower surface tension depending on the amount of the compound. Therefore, it becomes possible to finely control the transferability of the ink according to the printing conditions and the like. Here, when the amount of the fluorine compound mixed exceeds the above range, other physical properties of the polymer (normal physical properties, swelling, etc.) are deteriorated, and when the amount of the fluorine compound mixed is less than the above range, almost no decrease in surface tension is observed.

The surface-modified polymer of the present invention can be preferably used as the surface printing layer of the offset blanket for printing as described above. That is, the offset blanket usually consists of a support layer and a surface printing layer laminated on the support layer. And without changing other physical properties as described above as the surface printing layer,
By reducing the surface tension to the optimum range of ink transfer, an offset blanket that can almost completely satisfy two conflicting requirements of ink transfer from the plate to the offset blanket and ink transfer from the offset blanket to the substrate. Can be provided.

The surface printing layer is prepared by mixing the polymer with a vulcanizing agent, a filler and the like together with the above surface modifier and molding the mixture.
It is formed by vulcanization by a conventional method. Examples of the vulcanizing agent include benzoyl peroxide, bis 2,
4-dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, p-monochlorobenzoyl peroxide, 2,5-dimethyl-
2,5-bis (t-butylperoxy) hexane, t-
Examples thereof include organic peroxide-based crosslinking agents such as butylcumyl peroxide.

As the filler, anhydrous silicic acid, hydrous silicic acid, calcium carbonate, hard clay, barium sulfate, talc,
Inorganic fillers such as asbestos and graphite and recycled rubber,
Examples thereof include powder rubber, asphalt, styrene resin, and organic filler such as glue. As the support layer for laminating the surface printing layer having the above structure, for example, a plurality of base fabrics impregnated with a rubber material (rubber paste) and at least one compressible layer provided as needed are laminated. The ones created by

The base cloth is a woven cloth such as cotton, polyester and rayon. Examples of the rubber material to be impregnated include acrylonitrile-butadiene copolymer rubber and chloroprene rubber. These rubber materials contain a predetermined amount of a vulcanizing agent, a vulcanization accelerator and, if necessary, a thickener. Then, the woven cloth is coated with the rubber agent by an appropriate application means such as a blade coating method. Then, the surface printing layer forming rubber paste made of the above-mentioned specific rubber material is applied to the surface of the support layer through the primer layer and dried, or a sheet-like material formed by a calendar or the like is laminated. The obtained laminate is heated and pressurized at a predetermined pressure and temperature to be vulcanized to obtain an offset blanket having a compressive layer in the support layer. The compressive layer is prepared by applying a rubber paste prepared by dissolving a water-soluble powder such as salt to at least one intermediate base cloth, drying and vulcanizing it, and then applying 6 to 10 to 10 to 100 ° C. hot water. It is formed by immersing for a time, eluting the water-soluble powder and drying.

Further, instead of such a laminated type support layer, a film or sheet such as polyethylene terephthalate (PET), polycarbonate (PC), polypropylene (PP), aluminum foil, and a stainless sheet is used as the support layer. Good. The obtained offset blanket is used by being adhered to the peripheral surface of the cylinder of the transfer cylinder either directly or through an undercoating material.

Although the surface-printed layer of the offset blanket has been described as the use of the surface-modified polymer of the present invention, the polymer of the present invention is not limited to such use, and surface tension is a problem. It goes without saying that it can be used in various applications. Such applications include, for example, those that require sliding properties, such as automobile wipers, that require water resistance and solvent resistance, and those that require non-adhesive and solvent resistance, such as valve parts. Polymers that can be used.

[0020]

【Example】

Examples 1 to 6 Commercially available silicone rubber (trade name "KE-575u" manufactured by Shin-Etsu Silicone Co., Ltd.) was used as a polymer, and a perfluoroalkyl acrylate (Daikin Industries Co., Ltd.) as a surface modifier together with a vulcanizing agent. Product name "Daifree F
B-975 ") was added at the ratio shown in Table 1 and kneaded with a kneading roll. This was press-vulcanized in a mold at 165 ° C for 15 minutes, and then secondary vulcanized in an electric oven at 200 ° C for 4 hours.

The results of the surface tension, normal state test and swelling test of each of the obtained samples are also shown in Table 1. The surface tension of the polymer is calculated by using n-alkane as a solvent,
The contact angle of the droplet formed by the solvent on the polymer surface was measured and determined from Zisman Plot. Contact angle is Kyowa Interface Science
It was measured with a contact angle meter CA-A type manufactured by Co., Ltd.

The normal state test was determined according to JIS-6301. The test items in Table 1 are as follows. M ₁₀₀ : Tensile strength per unit area when the marked line distance extends 100% from the initial state. M ₂₀₀ : Tensile strength per unit area when the marked line distance is extended by 200% from the initial state.

M ₃₀₀ : The marked line distance is 300% from the initial state
It is the tensile strength per unit area when stretched. E _B: is the ratio of the elongation at break of the sample. T _B : Tensile strength at break of sample. H _S : Hardness by A-type hardness tester Swelling test is conducted for each sample (dimensions: 0.5 mm × 2 cm × 2 c
m) was immersed in toluene and ethanol kept at 40 ° C. for 24 hours respectively, and then the sample was taken out. From the weight W ₁ before immersion and the volume W ₂ after immersion, the weight change rate ΔW shown in the following formula Was measured.

ΔW (%) = [(W ₂ −W ₁ ) / W ₁ ] × 100 Further, the volume change rate ΔV shown in the following formula is calculated from the volume V ₁ before immersion and the volume V ₂ after immersion. did. ΔV (%) = [(V ₂ −V ₁ ) / V ₁ ] × 100

[0025]

[Table 1]

Comparative Examples 1 to 6 Comparative Examples 1 to 6 were carried out except that tetrafluoroethylene resin (PTFE, trade name “Lubron” manufactured by Daikin Industries, Ltd.) was used instead of the perfluoroalkyl acrylate in Examples 1 to 6. Each sample was obtained and its physical properties were measured in the same manner as in Examples 1 to 6. The results are shown in Table 2.

[0027]

[Table 2]

From Tables 1 and 2, in Comparative Examples 1 to 6, when the tetrafluoroethylene resin was mixed into the silicone rubber, the surface tension did not change so much and the physical properties of normal state and swelling were deteriorated. On the other hand, in the examples, when perfluoroalkyl acrylate is mixed into the silicone rubber as the surface modifier, only the surface tension is decreased according to the mixed amount without substantially changing the physical properties of the normal state and the swelling. I understand. In the comparative example, the reason why the physical properties are deteriorated is considered that the tetrafluoroethylene resin is hard to be compatible with the silicone rubber. Examples 7 to 12 Instead of the silicone rubber in Examples 1 to 6, NBR
(N230S manufactured by Nippon Synthetic Rubber Co., Ltd.) was used to prepare the compositions shown in Table 3, and press vulcanization was performed at 140 ° C. for 60 minutes, and no secondary vulcanization was performed. Each sample was obtained in the same manner as in Examples 1 to 6 and the physical properties thereof were measured. The results are shown in Table 3.

[0029]

[Table 3]

Comparative Examples 7 to 12 Comparative Examples 7 to 12 were carried out except that tetrafluoroethylene resin (PTFE, trade name "Lubron" manufactured by Daikin Industries, Ltd.) was used in place of the perfluoroalkyl acrylate in Examples 7 to 12. Each sample was obtained and its physical properties were measured in the same manner as in Examples 7 to 12. The results are shown in Table 4.

[0031]

[Table 4]

From the test results of Tables 3 and 4, similarly to the above, in Examples 7 to 12, the physical properties of the normal state and the swelling were hardly changed, and only the surface tension was decreased according to the mixed amount. On the other hand, in Comparative Examples 7 to 12, it can be seen that the surface tension does not change so much and the physical properties of normal state and swelling are deteriorated.

[0033]

Industrial Applicability As described above, according to the present invention, the surface modifier for a polymer has a surface modification site for reducing the surface tension of the polymer and a site reactive with the polymer in the molecule. The surface tension of the polymer can be reduced according to the amount of the fluorine compound contained in the polymer, while the other physical properties of the polymer are hardly changed.

[Procedure amendment]

[Submission date] January 30, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025]

[Table 1]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

[0027]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C08L 101/00 LSY 7167-4J

Claims (4)

[Claims] 1. A surface modifier for a polymer, which comprises a fluorine compound having in the molecule a surface modification site for lowering the surface tension of the polymer and a site reactive with the polymer. 2. The polymer surface modifier according to claim 1, wherein the surface modification site is a perfluoroalkyl group, and the reactive site is an acryloyloxy group or a methacryloyloxy group. 3. A polymer containing a surface-modifying agent comprising a fluorine compound having a surface-modifying site for lowering the surface tension of the polymer and a reactive site for the polymer in the polymer in an amount of 0.5 to 30 phr. A surface-modified polymer characterized by being mixed in a proportion. 4. The surface-modified polymer according to claim 3, wherein the polymer is silicone rubber or acrylonitrile-butadiene copolymer rubber.