JP2007296678A - Blanket for printing and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blanket for printing which is excellent in delivering properties and capable of forming a printing image having a good image quality (dot reproducibility/forming properties). <P>SOLUTION: The blanket for printing is constituted by forming a surface rubber layer in lamination on a base layer. The surface of the surface rubber layer is treated with a surface treating agent which comprises a fluorine-containing compound expressed by formula (F1) (wherein R<SB>F</SB>denotes a group containing a fluoroalkyl group, R<SP>1</SP>an alkyl group or an alkoxyalkyl group, R<SP>2</SP>and R<SP>3</SP>the same or different hydrogen atoms or univalent organic groups, x an integer of 1-100 and y an integer of 0-100), a tetraalkoxysilane, a tetraalkoxytitanium, a silane coupling agent and a solvent that dissolves these. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a blanket for offset printing that is excellent in paper discharge performance and can form a good print image.

  The blanket for offset printing has a surface rubber layer laminated on a base material layer that is bonded to a base fabric. A compressive type is used.

  In a blanket for offset printing, good paper discharge properties (non-adhesiveness to paper) are required. The paper discharge performance of the blanket can be improved to some extent by roughening the surface rubber layer or increasing the hardness.

  However, when the surface rubber layer is roughened, the halftone dot reproducibility of the printed image tends to be impaired. Moreover, when the surface rubber layer is made hard, there is a tendency that the solid inking property is lowered.

Conventionally, as a technique for improving paper discharge performance and image quality in a printing blanket, a technique for forming a surface rubber layer with a blend rubber of oil-resistant rubber and polysulfide rubber (see Patent Document 1), a specific physical A technique for forming a surface rubber layer from a rubber material having properties (see Patent Documents 2 to 3), a technique for forming a surface rubber layer from a rubber material containing a specific amount of bound acrylonitrile nitrile rubber (see Patent Document 4), Techniques for making the surface rubber layer a specific surface shape (see Patent Documents 5 to 6) have been introduced.
JP-A-5-85080 JP-A-8-52954 JP-A-8-52955 Japanese Patent Laid-Open No. 11-91260 JP-A-5-177968 JP-A-9-76658

  However, if the surface rubber layer is made of a specific rubber material (Patent Documents 1 to 4) or only a specific surface shape (Patent Documents 5 to 6), the paper discharge performance and the quality of the printed image (network Both point reproducibility and inking properties cannot be fully satisfied.

  The present invention has been made based on the circumstances as described above, and its purpose is to form a printed image having excellent paper discharge performance and good image quality (halftone dot reproducibility / inking properties). It is to provide a printing blanket that can be used.

The printing blanket of the present invention is a printing blanket obtained by laminating and forming a surface rubber layer on a base material layer, and the surface of the surface rubber layer is a fluorine-containing compound (hereinafter referred to as formula (F1)). , “Specific fluorine-containing compound”) and a tetraalkoxysilane represented by the formula (1): Si (OR ⁴ ) ₄ (wherein R ⁴ represents an alkyl group having 1 to 4 carbon atoms). And tetraalkoxytitanium represented by formula (2): Ti (OR ⁵ ) ₄ (wherein R ⁵ represents an alkyl group having 2 to 4 carbon atoms), and formula (3): Si (OR ^{6 _{) m R 7 3-m -}} (CH 2) n -R 8 ( wherein, R ⁶ represents an alkyl group or an alkoxyalkyl group, R ⁷ represents an alkyl group, m is an integer of 1 to 3, n is an integer of 0 to 5. also, R ⁸ is an organic reactive with the polymer backbone of rubber A surface treatment agent (hereinafter also referred to as “specific surface treatment agent”) containing a silane coupling agent represented by the formula (1) and a solvent for dissolving them. And

(Wherein R _F represents a group containing a fluoroalkyl group, R ¹ represents an alkyl group or an alkoxyalkyl group, and R ² and R ³ represent the same or different hydrogen atoms or monovalent organic groups. X is an integer from 1 to 100, and y is an integer from 0 to 100.)

The specific fluorine-containing compound constituting the specific surface treatment agent has a plurality of hydrolyzable groups (—OR ¹ ) in the molecule, and the tetraalkoxysilane has four alkoxy groups (—OR ⁴ ) in the molecule. And tetraalkoxytitanium also has four alkoxy groups (—OR ⁵ ) in the molecule. The silane coupling agent has a hydrolyzable group (—OR ⁶ ) and a reactive organic functional group (—R ⁸ ) in the molecule.

A specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium, and a silane coupling agent react (hydrolysis / condensation reaction) on the surface (surface to be treated) of the surface rubber layer constituting the printing blanket. As a result, a surface treatment film made of a hybrid compound (a compound containing fluorine atoms and having a SiO ₂ —TiO ₂ -based cross-linking structure) is formed, and the fluorine atoms and the cross-linking structure constituting this surface treatment film (hybrid compound) Thus, the surface of the surface rubber layer is imparted with excellent non-adhesiveness to paper, and as a result, the printing blanket of the present invention has excellent paper discharge performance. In particular, a surface-treated film having a SiO ₂ —TiO ₂ -based crosslinked structure is non-adhesive to paper compared to a surface-treated film having a SiO ₂ -based crosslinked structure (a surface-treated film comprising a fluorine-containing crosslinked polysiloxane). Property imparting effect (adhesive strength reducing effect) is excellent.

In addition, a reactive organic functional group (—R ⁸ ) derived from the silane coupling agent is introduced into the hybrid compound (or the structure in the formation process) constituting the surface treatment film. Reacts with the polymer main chain of the rubber constituting the surface rubber layer. As a result, the hybrid compound is chemically bonded to the polymer main chain of the rubber constituting the surface rubber layer via the silane coupling agent. Thus, a chemical bond is formed between the polymer main chain of the rubber constituting the surface rubber layer and the surface treatment film made of the hybrid compound via the silane coupling agent. The film adheres firmly to the surface rubber layer. Therefore, the non-stickiness imparted to the surface of the surface rubber layer is stably expressed over a long period of time.

  In addition, the surface-treated film made of a hybrid compound bonded to the polymer chain of rubber is excellent in thermal stability and chemical stability, and can be used for various organic solvents that are good solvents for specific fluorine-containing compounds. It becomes insoluble or hardly soluble. Thereby, even if the ink containing the organic solvent is brought into contact with the surface rubber layer, a part of the hybrid compound is not eluted, and the non-adhesiveness imparted thereby is not substantially impaired.

In the printing blanket of the present invention, the following forms are preferable.
(1) y in the above formula (F1) indicating a specific fluorine-containing compound is 0.
(2) In the above formula (F1) showing a specific fluorine-containing compound, the group containing a fluoroalkyl group represented by R _F is —CF ₃ , —C ₂ F ₅ , —C ₃ F ₇ , —C ₆ F ₁₃ , —C ₇ F ₁₅ or —CF (CF ₃ ) [OCF ₂ CF (CF ₃ )] _p OC ₃ F ₇ (wherein p is 0, 1 or 2) Be.
(3) The tetraalkoxysilane is tetramethoxysilane (TMOS) or tetraethoxysilane (TEOS).
(4) The tetraalkoxy titanium is at least one selected from tetraethoxy titanium, tetraisopropoxy titanium and tetrabutoxy titanium.
(5) The specific surface treatment agent contains an acid.
(6) The film thickness of the surface treatment film with the specific surface treatment agent is 0.001 to 10 μm, further 0.01 to 2 μm, particularly 0.1 to 1.5 μm.

  The production method of the present invention includes a step of applying a specific surface treatment agent to the surface of the surface rubber layer, and a step of heating a coating film by the surface treatment agent.

  The printing blanket of the present invention is excellent in paper discharge performance, and can form a printed image with good image quality such as halftone dot reproducibility and fillability.

Hereinafter, the present invention will be described in detail.
FIG. 1 is a cross-sectional view schematically showing an example of the layer structure of the printing blanket of the present invention.
The blanket shown in the figure is formed by laminating a surface rubber layer 30 on a base material layer 10 with an adhesive rubber layer 20 interposed therebetween.

  The base material layer 10 is formed by laminating a first base cloth 111, a sponge layer (compression layer) 12, a second base cloth 112, an adhesive rubber layer 13, and a third base cloth 113. ing.

  As the first base cloth 111, the second base cloth 112, and the third base cloth 113 constituting the base material layer 10, a cotton cloth is usually used.

The sponge layer 12 provided between the first base fabric 111 and the second base fabric 112 provides suitable compression characteristics for the blanket, and reduces printing pressure to enable good printing. Any layer formed.
Examples of the constituent material of the sponge layer 12 include sponge rubber made of nitrile rubber or the like, and the sponge rubber constituting the sponge layer 12 may be open-cell type or closed-cell type.

  The adhesive rubber layer 13 provided between the second base cloth 112 and the third base cloth 113 is an adhesive layer for bonding them. As a constituent material of the adhesive rubber layer 13, nitrile rubber can be exemplified.

  The adhesive rubber layer 20 provided between the base material layer 10 and the surface rubber layer 30 is a rubber-based adhesive layer for bonding them.

  The surface rubber layer 30 is a layer for receiving and transferring ink, and is made of, for example, nitrile rubber.

  The hardness of the surface rubber layer 30 is preferably 45 to 60, more preferably 50 to 55, according to a JIS-A hardness meter. When the hardness of the surface rubber layer is excessive, the solid inking property tends to decrease. On the other hand, when the hardness is too small, the pressure is not sufficiently applied, and it is likely to cause poor acceptance and transfer failure.

The surface roughness (Rz) of the surface rubber layer 30 is preferably 3.0 to 10.0 μm, more preferably 4.0 to 6.0 μm.
When the surface roughness (Rz) of the surface rubber layer 30 is excessive, the halftone dot reproducibility is lowered, and a clear printed image cannot be formed.

  The printing blanket of the present invention is characterized in that the surface of the surface rubber layer constituting the printing blanket is treated with a specific surface treatment agent. This surface treatment agent contains a specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium, a silane coupling agent, and a solvent.

The specific fluorine-containing compound has a group (R _F ) containing a fluoroalkyl group at both molecular ends and a group (trialkoxysilyl group or trialkoxyalkoxysilyl group) represented by —Si (OR ¹ ) _3. It is a fluorine-based oligomer having an intermediate chain formed by bonding and further having an intermediate chain represented by (—CH ₂ —CR ² R ³ —).

Specific examples of the group (R _F ) containing a fluoroalkyl group constituting the specific fluorine-containing compound include —CF ₃ , —C ₂ F ₅ , —C ₃ F ₇ , —C ₆ F ₁₃ and —C _7. fluoroalkyl group represented by -C like _{F 15 q F 2q + 1 (} q = 1~10); -CF (CF 3) OC 3 F 7, -CF (CF 3) [OCF 2 CF (CF 3) ] Exemplifying a group represented by OC ₃ F ₇ and —CF (CF ₃ ) [OCF ₂ CF (CF ₃ )] ₂ OC ₃ F ₇ (a group containing an oxyfluoroalkylene group and a fluoroalkyl group) Among these, a group represented by —CF (CF ₃ ) OC ₃ F ₇ is particularly preferable.

Specific examples of the group represented by —Si (OR ¹ ) ₃ having an essential intermediate chain constituting a specific fluorine-containing compound include trialkoxysilyl groups such as trimethoxysilyl group and triethoxysilyl group; tri (methoxy Mention may be made of trialkoxyalkoxysilyl groups such as methoxy) silyl group, tri (methoxyethoxy) silyl group, tri (ethoxymethoxy) silyl group and tri (ethoxyethoxy) silyl group. Of these, trialkoxysilyl groups are preferred, and trimethoxysilyl groups are particularly preferred.

The groups (R ² , R ³ ) constituting any intermediate chain (—CH ₂ —CR ² R ³ —) in a specific fluorine-containing compound are the same or different groups, and are hydrogen atoms or monovalent organic groups It is. Examples of the organic group represented by R ² or R ³ include groups represented by the following formulas (i) to (v).

In the above formula (F1) showing a specific fluorine-containing compound, the number (x) of essential intermediate chains is 1 to 100, preferably 1 to 50, more preferably 1 to 10, particularly preferably 2 to 5. Is done.
Moreover, the number (y) of arbitrary intermediate chains is 0 to 100, preferably 0 to 50, and more preferably 0 to 10.

  Examples of suitable compounds constituting the specific fluorine-containing compound include compounds represented by the following formulas (4) to (8). In particular, the compound represented by the following formula (4) or formula (5) [compound in which y in the above formula (F1) is 0] is a fluorine atom (atom imparting non-adhesiveness) in one molecule. Since the ratio is large, fluorine atoms can be present on the surface of the surface rubber layer with high efficiency.

(Wherein x 'is 2 or 3)

[In Formula (5) and Formula (6), R _F ′ is a group represented by the formula: —CF (CF ₃ ) OCF ₂ CF (CF ₃ ) OC ₃ F ₇ .
In formula (5), xa is an integer of 1-100.
In formula (6), xb is an integer of 1 to 100, and yb is an integer of 1 to 500. ]

[In Formula (7), xc is an integer of 1-10, yc is an integer of 0-100. In formula (8), xd is an integer of 1 to 10, and yd is an integer of 0 to 100. ]

In the presence of a fluorine-containing peroxide represented by the following formula (F1A), the specific fluorine-containing compound represented by the above formula (F1), the monomer represented by the following formula (F1B), and the following formula (F1C ) Can be obtained by polymerizing with a monomer represented by
In this reaction product (fluorine-containing compound), an oligomer in which a group (R _F ) containing a fluoroalkyl group is introduced only at one end may be contained in an arbitrary ratio.

(Wherein R _F , R ¹ , R ² and R ³ are as defined above.)

  The content ratio of the specific fluorine-containing compound in the specific surface treatment agent is preferably 0.001 to 20% by mass, more preferably 0.005 to 10% by mass, and particularly preferably 0.01 to 5% by mass. %. When the content ratio of the specific fluorine-containing compound is too small, it becomes difficult to impart a sufficient treatment effect (non-adhesiveness) to the surface of the surface rubber layer. On the other hand, even if a specific fluorine-containing compound is contained in a proportion exceeding 20% by mass, a treatment effect commensurate with the content cannot be obtained.

The tetraalkoxysilane constituting the specific surface treatment agent is a tetrafunctional alkoxysilane represented by the formula (1): Si (OR ⁴ ) ₄ .
In the formula (1) indicating tetraalkoxysilane, R ⁴ represents an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, or a butyl group. Specific examples of the tetraalkoxysilane include tetramethoxysilane (TMOS) and tetraethoxysilane (TEOS), and TEOS is particularly preferable.

The content of the tetraalkoxysilane in the specific surface treatment agent is preferably 0.5 to 1000 times (mass), more preferably 1 to 500 times, particularly preferably the content of the specific fluorine-containing compound. 1 to 200 times.
If the tetraalkoxysilane content (relative to the specific fluorine-containing compound) is too small, the formation of a crosslinked structure becomes insufficient and the surface of the surface rubber layer is completely covered (film formation) ) Becomes difficult. On the other hand, when this ratio is excessive, it is difficult to impart a sufficient treatment effect (non-adhesiveness) to the surface of the surface rubber layer.

The tetraalkoxytitanium constituting the specific surface treatment agent is a tetrafunctional alkoxytitanium represented by the formula (2): Si (OR ⁵ ) ₄ .
By including tetraalkoxytitanium as an essential component of a specific surface treatment agent, a surface treatment film (SiO ₂ —TiO ₂ -based crosslinked structure that is particularly excellent in non-adhesiveness imparting effect (adhesion reducing effect) Having a hybrid compound).

In the above formula (2) indicating tetraalkoxytitanium, R ⁵ represents an alkyl group having 2 to 4 carbon atoms such as an ethyl group, a propyl group, an isopropyl group, or a butyl group. Specific examples of the tetraalkoxysilane include tetraethoxytitanium, tetraisopropoxytitanium and tetrabutoxytitanium, and tetraethoxytitanium is particularly preferable.

The content of tetraalkoxytitanium in the specific surface treatment agent is preferably 0.001 to 20 times (mass), more preferably 0.1 to 10 times, particularly the content of the specific fluorine-containing compound. Preferably it is 2 to 5 times.
Moreover, it is preferable that content of tetraalkoxy titanium is 1-10 mass% of tetraethoxysilane, More preferably, it is 2-5 mass%.
When the content ratio of tetraalkoxy titanium (relative ratio with respect to tetraalkoxysilane) is too small, it becomes difficult to impart a sufficient treatment effect (non-adhesiveness) to the surface of the surface rubber layer. On the other hand, when the content ratio of tetraalkoxytitanium (relative ratio with respect to tetraalkoxysilane) is excessive, the obtained surface treatment agent is cured in a short time, and workability such as coating property is deteriorated.

The silane coupling agent constituting the specific surface treatment agent is represented by the formula (3): Si (OR ⁶ ) _m R ⁷ _3-m — (CH ₂ ) _n —R ⁸ .
In the above formula (3) showing a silane coupling agent, R ⁶ represents an alkyl group or an alkoxyalkyl group, R ⁷ represents an alkyl group, m is an integer of 1 to 3, preferably 3, and n is 0 An integer of -5, preferably an integer of 0-3. R ⁸ represents an organic functional group having reactivity with the polymer main chain of rubber.
In the above formula (3), the group represented by Si (OR ⁶ ) _m R ⁷ _3-m — has at least one, preferably three hydrolyzable groups (—OR ⁶ ). Thereby, the silane coupling agent represented by the above formula (3) is tetraalkoxysilane having ^four alkoxy groups (—OR ⁴ ), tetraalkoxy titanium having four alkoxy groups (—OR ⁵ ), and It can react with any of the specific fluorine-containing compounds having a plurality of hydrolyzable groups (—OR ¹ ).
Here, the group represented by Si (OR ⁶ ) _m R ⁷ _3-m — is preferably a trialkoxysilyl group such as a trimethoxysilyl group or a triethoxysilyl group.

Examples of the organic functional group (-R ⁸ ) having reactivity with the polymer main chain of rubber include an amino group, a mercapto group, a vinyl group, a (meth) acryloyloxy group, an epoxy group, and a ureido group. it can. Among these, preferred are a mercapto group having reactivity with a polymer main chain of a rubber having an unsaturated bond, and a vinyl group having reactivity with a polymer main chain of a rubber having no unsaturated bond. be able to.
Thus, by selecting the reactive organic functional group (—R ⁸ ) according to the type of rubber (such as the presence or absence of an unsaturated bond in the polymer main chain), the same type as the specific fluorine-containing compound This compound can be used for various rubbers (rubber constituting the surface rubber layer).

On the surface of the surface rubber layer, a specific fluorine-containing compound, (—OR ¹ ), tetraalkoxysilane (—OR ⁴ ), tetraalkoxytitanium (—OR ⁵ ), and a silane coupling agent (—OR ⁶ ) By the reaction (hydrolysis / condensation reaction), a surface treatment film made of a hybrid compound containing a fluorine atom and having a SiO ₂ —TiO ₂ cross-linked structure is formed.

Thus, in the structure of the hybrid compound constituting the surface treatment film or the formation process (hydrolysis / condensation reaction process), a reactive organic functional group (—R ⁸ ) derived from the silane coupling agent is present. When introduced, this organic functional group (—R ⁸ ) reacts with the polymer main chain of the rubber constituting the surface rubber layer. As a result, the hybrid compound is chemically bonded to the polymer main chain of the rubber constituting the surface rubber layer via the silane coupling agent.

  Thus, a chemical bond is formed between the polymer main chain of the rubber constituting the surface rubber layer and the surface treatment film made of the hybrid compound via the silane coupling agent. The film adheres firmly to the surface rubber layer. Therefore, the surface treatment film is not detached, and the non-tackiness imparted to the surface of the surface rubber layer is stably expressed.

In the specific surface treatment agent, the content of the silane coupling agent is preferably 0.01 to 10 times (mass), more preferably 0.05 to 5 times the content of the specific fluorine-containing compound. Particularly preferably, it is 0.1 to 5 times.
When the content ratio of the silane coupling agent (relative ratio with respect to the specific fluorine-containing compound) is too small, the surface treatment film formed by the surface treatment agent obtained is sufficiently adhered to the surface rubber layer It will not have sex. On the other hand, when this ratio is excessive, it is difficult to impart a sufficient treatment effect (non-adhesiveness) to the surface of the surface rubber layer.

  The solvent constituting the specific surface treatment agent can be selected from those which can dissolve any of the specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium and silane coupling agent. Examples of the organic solvent include hexane, methanol, ethanol, tetrahydrofuran, dichloromethane, chloroform, benzene, ethyl acetate, dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), toluene, and acetone. Of these, hexane, methanol, ethanol, dichloromethane and acetone are preferred.

The specific surface treatment agent may contain various optional components in addition to the essential components as long as the effect is not impaired.
A viewpoint that promotes the formation of a crosslinked structure in a hybrid compound by efficiently performing a reaction (hydrolysis / condensation reaction) of a specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium, and a silane coupling agent. Therefore, the specific surface treatment agent is preferably acidic (pH is 6 or less, particularly 2 to 5).

  The acid contained to make the specific surface treatment agent acidic may be an inorganic acid or an organic acid. Here, examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid and the like, and hydrochloric acid is preferable. Examples of the organic acid include formic acid, acetic acid, propionic acid, butanoic acid and pentanoic acid, and acetic acid is preferred.

The specific surface treatment agent can be easily prepared by dissolving a specific fluorine-containing compound, tetraalkoxysilane, tetraalkoxytitanium, silane coupling agent, and optional components in a solvent.
In addition, when the obtained surface treating agent is left still for a long time at room temperature, there exists a possibility that the condensate of a structural component (especially tetraalkoxysilane and tetraalkoxytitanium) may be formed and a precipitate may be produced. For this reason, it is preferable to use a specific surface treatment agent within 24 hours after production, and it is important to homogenize the surface treatment agent by sufficiently stirring (for example, 1 to 6 hours) before use. It is. Moreover, you may heat to 60-70 degreeC as needed.

  The printing blanket of the present invention heats a coating film formed by applying a specific surface treatment agent to the surface (surface to be treated) of the surface rubber layer (hereinafter referred to as “coating step”). And a manufacturing method including a process (hereinafter referred to as “heating process”).

The method for applying the specific surface treatment agent in the application step is not particularly limited, but since the surface treatment film can be made thin, application by spraying, application by immersion, and the like are preferable.
In addition, after completion | finish of this application | coating process, in order to remove a solvent from the coating film formed in the surface of a surface rubber layer, you may perform a drying process. The drying condition varies depending on the type and content ratio of the solvent contained in the surface treatment agent, but is, for example, 1 minute to 24 hours at room temperature, and preferably 3 minutes to 1 hour.
In the heating step, the method for heating the coating film is not particularly limited, such as heating with an oven or heating with a hot press. The heating condition is, for example, 50 to 200 ° C. and 5 minutes to 24 hours.

By heating a coating film with a specific surface treatment agent formed on the surface of the surface rubber layer, (i) a specific fluorine-containing compound (—OR ¹ ), tetraalkoxysilane (—OR ⁴ ), and tetraalkoxy While the reaction of titanium (—OR ⁵ ) and the silane coupling agent (—OR ⁶ ) (crosslinking structure formation reaction by hydrolysis / condensation) proceeds, (ii) the reactive organic functionality of the silane coupling agent The reaction between the group (—R ⁸ ) and the polymer main chain of the rubber constituting the surface rubber layer proceeds.

  Thereby, a chemical bond is formed between (i) the hybrid compound constituting the surface treatment film and the silane coupling agent, and (ii) between the silane coupling agent and the polymer main chain of the rubber, As a result, a surface-treated film excellent in adhesion to the surface rubber layer (durability and toughness as a film) is formed.

And, by the fluorine atoms and the crosslinked structure constituting this surface treatment film (hybrid compound), the surface of the surface rubber layer is given excellent non-adhesiveness to paper. As a result, the printing blanket of the present invention Excellent paper discharge performance. In particular, a surface treatment film having a crosslinked structure (SiO ₂ —TiO ₂ -based crosslinked structure) containing a Ti—O bond derived from tetraalkoxytitanium is a surface treatment film having a SiO ₂ -based crosslinked structure (fluorine-containing crosslinked polymer). Compared with a surface-treated film made of siloxane, the non-adhesiveness imparting effect (adhesive force reducing effect) is excellent.
The surface treatment film made of the hybrid compound is firmly adhered to the rubber constituting the surface rubber layer, so that the surface treatment film is not detached and applied to the surface of the surface rubber layer. The non-tackiness that has been produced is stably expressed.

  Further, the surface treatment film made of a hybrid compound is excellent in thermal stability and chemical stability, and becomes insoluble or hardly soluble in various organic solvents which are good solvents for a specific fluorine-containing compound. Thereby, even if the ink containing the organic solvent is brought into contact with the surface rubber layer, a part of the hybrid compound is not eluted, and the non-tackiness imparted thereby is not substantially impaired.

In the printing blanket of the present invention, the thickness of the surface treatment film formed on the surface rubber layer is preferably 0.001 to 10 μm, more preferably 0.01 to 2 μm, particularly preferably 0.1 to 0.1 μm. 1.5 μm.
If the surface treatment film is 0.001 μm or more, the surface of the surface rubber layer can be uniformly coated, and the desired non-adhesiveness can be expressed on the surface of the blanket (surface of the surface treatment film).
Moreover, when the film thickness of the surface treatment film is 10 μm or less, the hardness of the blanket surface (surface of the surface treatment film) can be made substantially the same as the hardness of the surface rubber layer (rubber base material). (The blanket surface is not cured by the surface treatment). Furthermore, even if the surface of the surface rubber layer has a special shape, a surface treatment film can be formed following the shape (the surface shape is not changed by the surface treatment).

  The printing blanket of the present invention has an excellent paper discharge property because the surface of the surface rubber layer constituting the printing blanket is treated with a specific surface treatment agent (a surface treatment film is formed). Further, the printed image formed by the printing blanket of the present invention is excellent in image quality such as halftone dot reproducibility and inking property.

  Examples of the present invention will be described below, but the present invention is not limited thereto.

<Example 1>
(1) Preparation of specific surface treatment agent:
According to the formulation shown in Table 1 below, the specific fluorine-containing compound represented by the above formula (4) [wherein, the molar ratio of “(x ′ = 2) / (x ′ = 3)” is 86/14 thing. same as below. ] 0.004 g, tetraethoxysilane (TEOS) 0.40 g, tetraethoxy titanium [Ti (OEt) ₄ ] 0.008 g, and represented by the formula: Si (OCH ₃ ) ₃ — (CH ₂ ) ₃ —SH Silane coupling agent “A-189” (manufactured by Nihon Unicar Co., Ltd.) and hydrochloric acid (0.1N) 0.05 g were added to 9.5 g of acetone. By stirring for a certain time, a specific surface treatment agent (specific fluorine-containing compound concentration = 0.04 mass%, TEOS concentration = 4.0 mass%, tetraethoxy titanium concentration = 0.08 mass%, silane coupling agent concentration = 0.1% by mass).

(2) Surface treatment (application process and heating process):
A blanket material having a layer structure shown in FIG. 1 (not subjected to surface treatment with a specific surface treatment agent) was prepared. Details of each layer are as follows.

-Types of base fabrics (111) to (113): cotton fabric-Constituent material of sponge layer (12): Sponge rubber made of nitrile rubber-Constituent material of adhesive rubber layer (13): Adhesive of nitrile rubber-Adhesive rubber Constituent material of layer (20): Nitrile rubber adhesive-Constituent material of surface rubber layer (30): Nitrile rubber

  The surface treatment layer (30) of the blanket material was spray-coated with the specific surface treatment agent prepared by the above (1) (treatment agent immediately after completion of the stirring operation for 1 hour). Next, the blanket material is heat-treated in an oven at 150 ° C. for 10 minutes to form a surface treatment film (surface treatment film made of a hybrid compound) with a specific surface treatment agent on the surface rubber layer. The blanket was manufactured. The surface hardness (JIS-A) of this blanket was 52. Moreover, when the film thickness of the surface treatment film was measured by SEM, it was in the range of 0.5 to 1.2 μm.

<Example 2>
In accordance with the formulation shown in Table 1 below, the specific surface treatment agent (tetraethoxytitanium concentration = 0.12% by mass) was obtained in the same manner as in Example 1 (1) except that the amount of tetraethoxytitanium used was changed to 0.012 g. The blanket of the present invention in which a surface treatment film with a specific surface treatment agent is formed on the surface rubber layer in the same manner as in Example 1 (2) except that this surface treatment agent was used. Manufactured. The surface hardness (JIS-A) of this blanket was 52, and the film thickness of the surface treatment film was the same as that of the blanket according to Example 1.

<Example 3>
In accordance with the formulation shown in Table 1 below, a specific surface treatment agent (tetraethoxy titanium concentration = 0.20 mass%) was carried out in the same manner as in Example 1 (1) except that the amount of tetraethoxy titanium used was changed to 0.020 g. The blanket of the present invention in which a surface treatment film with a specific surface treatment agent is formed on the surface rubber layer in the same manner as in Example 1 (2) except that this surface treatment agent was used. Manufactured. The surface hardness (JIS-A) of this blanket was 52, and the film thickness of the surface treatment film was the same as that of the blanket according to Example 1.

<Example 4>
In accordance with the formulation shown in Table 1 below, the specific surface treatment agent (silane coupling agent concentration = 0.2) was used in the same manner as in Example 1 (1) except that the amount of the silane coupling agent was changed to 0.02 g. (Mass%) of the present invention, in which a surface treatment film with a specific surface treatment agent is formed on the surface rubber layer in the same manner as in Example 1 (2) except that this surface treatment agent was used. A blanket was manufactured. The surface hardness (JIS-A) of this blanket was 52, and the film thickness of the surface treatment film was the same as that of the blanket according to Example 1.

<Example 5>
In accordance with the formulation shown in Table 1 below, instead of the specific fluorine-containing compound represented by the above formula (4), the specific fluorine-containing compound represented by the above formula (6) (provided that xb = 1 to 10, yb is 1 10) A specific surface treatment agent was prepared in the same manner as in Example 1 (1) except that 0.004 g was used, and the same treatment as in Example 1 (2) was conducted except that this surface treatment agent was used. Thus, a blanket of the present invention in which a surface treatment film with a specific surface treatment agent was formed on the surface rubber layer was produced. The surface hardness (JIS-A) of this blanket was 52, and the film thickness of the surface treatment film was the same as that of the blanket according to Example 1.

<Comparative Example 1>
A blanket material similar to that prepared in Example 1 (2) was heat-treated in an oven at 150 ° C. for 10 minutes to produce a comparative blanket having no surface treatment film formed on the surface rubber layer. . The surface hardness (JIS-A) of this blanket was 52.

<Measurement of adhesive strength to paper (evaluation of paper discharge)>
Test specimens were collected from each of the blankets obtained in Examples 1 to 5 and Comparative Example 1, and the tackiness of the test specimens (the blanket surface portion) to the paper was measured using a tacking tester “TAC-II” [Co., Ltd. Substitute evaluation of “paper dischargeability” was performed by measuring using Resca. The results are also shown in Table 1. The measurement conditions are as follows.

(Measurement condition)
Probe: A cylindrical probe made of SUS304. However, a coated paper (OK top coat chrysanthemum size 50.5 kg) was affixed to the contact portion with the test piece (circular region having a diameter of 5.1 mm).
・ Entry speed: 5mm / min
・ Pressure: 100gf
・ Pressurization time: 3 seconds ・ Separation (separation) speed: 600 mm / min
・ Measurement temperature: Room temperature

<Print test>
Each of the blankets obtained in Examples 1 to 5 and Comparative Example 1 was subjected to a printing test according to the following conditions, etc., and evaluated for paper discharge performance, halftone dot reproducibility, and fillability. The results are also shown in Table 1.

・ Printing machine: Sheet-fed printing machine “DAIYA 1F” (Mitsubishi Heavy Industries, Ltd.)
・ Printing paper: Coated paper “OK Top Coat Chrysanthemum 50.5Kg” (Oji Paper Co., Ltd.)
: Medium quality paper “Heine Medium Quality Paper 55Kg” (Daiou Paper Co., Ltd.)
・ Printing ink: “TK High Unity Neo Indigo” (manufactured by Toyo Ink Manufacturing Co., Ltd.)
・ Dampening water: 3% IPA added ・ Printing conditions: 9000 prints / hour ・ Standard tailoring

(1) Evaluation method of paper discharge performance:
Using coated paper, 100 solid images were continuously printed under the same conditions, and the curl height of the 100th printed paper was measured. The smaller this value, the better the paper discharge performance.

(2) Method for evaluating halftone dot reproducibility:
Using coated paper, 10,000 sheets were printed at a solid density of 1.60. The density of each halftone dot of the 10,000th printed image was measured, and the relative contrast value was determined by the following equation. The higher this value, the better the dot reproducibility.

  Formula): Relative contrast value = (solid density−halftone dot density) / solid density

(3) Evaluation method of inking property:
The blanket according to Comparative Example 1 was wound around one side in the longitudinal direction of the cylinder, and the blanket according to Example 1 was wound around the other side in the longitudinal direction of the cylinder (two left and right sides). Using solid paper, the solid density by the blanket according to Example 1 when the solid density by the blanket according to Comparative Example 1 was printed at 1.20 was measured. The higher the concentration, the better the inking property.
The solid density was similarly measured for each of the blankets of Examples 2 to 5.

  The printing blanket of the present invention can be suitably used as a blanket for offset printing.

It is sectional drawing which shows typically an example of the laminated constitution of the printing blanket of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Base material layer 111 1st base fabric 112 2nd base fabric 113 3rd base fabric 12 Sponge layer 13 Adhesive rubber layer 20 Adhesive rubber layer 30 Surface rubber layer

Claims (10)

A printing blanket formed by laminating a surface rubber layer on a base material layer,
The surface of the surface rubber layer is
A fluorine-containing compound represented by the following formula (F1);
A tetraalkoxysilane represented by the formula (1): Si (OR ⁴ ) ₄ (wherein R ⁴ represents an alkyl group having 1 to 4 carbon atoms);
Tetraalkoxytitanium represented by formula (2): Ti (OR ⁵ ) ₄ (wherein R ⁵ represents an alkyl group having 2 to 4 carbon atoms);
Equation ^{(3): Si (OR 6} ) m R 7 3-m - (CH 2) n -R 8 ( wherein, R ⁶ represents an alkyl group or an alkoxyalkyl group, R ⁷ represents an alkyl group, m Is an integer of 1 to 3, n is an integer of 0 to 5. R ⁸ represents an organic functional group having reactivity with the polymer main chain of the rubber. When,
A surface treatment agent containing a solvent for dissolving them;
Blanket for printing being processed by.

(Wherein R _F represents a group containing a fluoroalkyl group, R ¹ represents an alkyl group or an alkoxyalkyl group, and R ² and R ³ represent the same or different hydrogen atoms or monovalent organic groups. X is an integer from 1 to 100, and y is an integer from 0 to 100.)   The printing blanket according to claim 1, wherein y in the formula (F1) representing the fluorine-containing compound is 0. In the formula (F1) representing the fluorine-containing compound, the group containing a fluoroalkyl group represented by R _F is -CF ₃ , -C ₂ F ₅ , -C ₃ F ₇ , -C ₆ F ₁₃ , -C ₇ F ₁₅ or _{-CF (CF 3) [OCF 2} CF (CF 3)] p OC 3 F 7 ( wherein, p is 0, 1 or 2.) claims a group represented by The printing blanket according to claim 1 or 2.   The printing blanket according to any one of claims 1 to 3, wherein the tetraalkoxysilane is tetramethoxysilane or tetraethoxysilane.   The printing blanket according to any one of claims 1 to 4, wherein the tetraalkoxytitanium is at least one selected from tetraethoxytitanium, tetraisopropoxytitanium, and tetrabutoxytitanium.   The printing blanket according to any one of claims 1 to 5, wherein the surface treatment agent contains an acid.   The printing blanket according to any one of claims 1 to 6, wherein a film thickness of the surface treatment film by the surface treatment agent is 0.001 to 10 µm.   The printing blanket according to any one of claims 1 to 6, wherein a film thickness of the surface treatment film by the surface treatment agent is 0.01 to 2 µm.   The printing blanket according to any one of claims 1 to 6, wherein a film thickness of the surface treatment film by the surface treatment agent is 0.1 to 1.5 µm. Applying the surface treatment agent according to claim 1 to the surface of the surface rubber layer;
A method for producing a blanket for printing, including a step of heating a coating film by the surface treatment agent.

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