JPH0136875B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has excellent printing properties, particularly with water-based inks such as fountain pens, water-based pens, and printer inks, and has ionizable properties that can provide a release layer with good release properties against adhesives. This invention relates to a radiation-curable releasable treatment agent.

Release agents are widely used as back-treatment agents for pressure-sensitive tape substrates and release agents for pressure-sensitive label separators. As release agents, polyorganosiloxanes, copolymers of acrylic esters, waxes, paraffins, etc. have been used or proposed, but the printing properties of the surface of the release layer, especially the printing properties when using water-based inks, still remain. is insufficient. Therefore, when printing on the back-treated surface of a pressure-sensitive tape or the non-adhesive surface of the release paper of a pressure-sensitive label, it is essential to treat it with a release agent that has both printability and peelability. However, there was no release agent suitable for such applications.

Furthermore, treated substrates that require such printability are required to have good writability and the feel of normal paper, so they are more likely to be treated with normal high-quality paper than processed paper such as resin-coated paper or film laminated paper. It is preferable to use paper without a seal, such as paper. However, with such unfilled paper, the release agent has a strong permeability into the base material, and conventional solvent or emulsion type release agents cannot provide a good release surface.

The main purpose of the present invention is to solve the above-mentioned problems, to enable easy coating even without a solvent if necessary, to cure quickly by irradiation with ionizing radiation, and to have good peelability. The object of the present invention is to provide a release agent that provides a release agent layer with good printability even for water-based inks.

The ionizing radiation curing type peeling treatment agent of the present invention includes:
It was developed to achieve the above-mentioned purpose, and more specifically, isocyanate 1 of component B)
The following A) and B) consist of 0.01 to 0.7 equivalents of active hydrogen in component C) and 0.8 to 1.2 equivalents in total of OH in component A) and active hydrogen in component C).
It consists of a urethane-modified organopolysiloxane containing a terminal unsaturated group, which is a substantially complete reaction product between components (C) and C), and is characterized by having printability.

A Organopolysiloxane represented by the following general formula (1) However, here, R ¹ and R ² are each a methyl, ethyl, propyl or trifluoropropyl group, x and y are each a positive number; m is an integer of 0 to 4; n is 2 to 3
B an organic polyisocyanate, and C an acrylate compound having at least one active hydrogen-containing group selected from a hydroxyl group, a carboxyl group, and an amino group in one molecule.

That is, in the releasable treatment agent of the present invention,
Organopolysiloxane (component A) as the main component has a polyether part with high hydrophilicity and an organopolysiloxane part that imparts releasability in its structure, and is structured like a block, so it has excellent hydrophilicity and releasability. Provides a release agent layer with both properties. In addition, the organic polyisocyanate component (component B) is effective in providing a release layer with good adhesion to the substrate, curability, and film strength, and the acrylate compound (component C) has ionizable properties. Provides good curing properties against radiation, especially electron beams.

The present invention will be explained in more detail below. In the following descriptions, "%" and "parts" indicate the composition.
are based on weight unless otherwise specified.

The organopolysiloxane which is the first main component of the releasable treatment agent of the present invention is represented by the above general formula (1), and the releasability can be controlled by the degree of polymerization y of the organopolysiloxane moiety. A range of 5 to 500, particularly 10 to 500 is preferably used. When the degree of polymerization y is less than 5, sufficient releasability cannot be obtained, and when it exceeds 500, printing suitability is slightly reduced. Furthermore, the polyether moiety (C _o H _2o O ₎ I can't get it. n
may be a mixture of 2 and 3, but its average value is also 2 to 3, preferably in the range of 2 to 2.5, particularly in view of providing good printing suitability for water-based inks. The degree of polymerization x of the polyether moiety is determined in relation to the degree of polymerization of the organopolysiloxane moiety so as to provide a good balance between the peelability and printability of the resulting release agent layer. That is, when the value of y/x becomes large and the organopolysiloxane portion becomes relatively large, the peeling force increases but the printing suitability deteriorates, and conversely, when the value of y/x becomes small and the polyether portion becomes small. , the printing suitability increases, but the peelability deteriorates. Therefore, a range of 0.5 to 10 is appropriate for y/x.

On the other hand, the total degree of polymerization of organopolysiloxane is 2x
+y affects the reactivity with polyisocyanate. If 2x+y is too small, a large amount of polyisocyanate will be required, resulting in adverse effects such as poor releasability. If 2x+y is too large, the degree of crosslinking of the release agent will decrease, resulting in a decrease in film strength or poor curing. Taking these points into consideration, x is selected from a range of 2 to 100.

The alkylene moiety C _n H _2n located between the organopolysiloxane moiety and the polyether moiety does not particularly need to exist, and in this case it has the advantage of being able to be produced at low cost. It has the advantage of increasing the stability of polysiloxane. However, organopolysiloxanes with m of 5 or more have no particular advantage in terms of performance, but are disadvantageous in terms of raw material availability, so m is 3.
or 4 is preferred, particularly 3 is most preferred.

Specific examples of organopolysiloxanes include the following.

As the polyisocyanate used in the present invention,
Aliphatic and aromatic polyisocyanates having two or more isocyanate groups in the molecule are used,
Specifically, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate,
3,3'-dimethyl 4,4'-diphenylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, trimethylhexamethylene diisocyanate, triphenylmethane triisocyanate, and etc. can be mentioned. These polyisocyanates may be used in combination.

Next, as the acrylate compound used in the present invention, one having at least one active hydrogen-containing group selected from hydroxyl group, carboxyl group, and amide group in one molecule is used. Ethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, 4-hydroxycyclohexyl acrylate, 5-hydroxycyclooctyl acrylate, 5-hydroxycyclooctyl methacrylate, 2-hydroxy-3 phenyl Oxypropyl acrylate, etc., as well as adducts of acrylic acid, methacrylic acid, or 2-hydroxyethyl acrylate with phthalic anhydride; compounds containing one active hydrogen group such as acrylamide, methacrylamide, N-methylolacrylamide, etc.; Furthermore, addition reaction products of acrylic acid and diepoxy compounds such as ethylene glycol diglycidyl ether dimethacrylate, diethylene glycol diglycidyl ether dimethacrylate, propylene glycol diglycidyl ether diacrylate, and phthalic acid diglycidyl ester diacrylate; or glycidyl acrylate or glycidyl Examples include reactants of methacrylate and dibasic acids. Specific dibasic acids include itaconic acid, maleic acid, fumaric acid, succinic acid, adipic acid, and terephthalic acid.

The above components A), B) and C) are in such amounts that the total amount of the organopolysiloxane (component A)) and the acrylate compound (component C)) is approximately equal to the equivalent weight of the polyisocyanate (component B)). Used in ratios. More specifically, the total amount of OH of component A) and active hydrogen of component C) is used within the range of 0.8 to 1.2 equivalents with respect to 1 equivalent of isocyanate of component B), and 1 equivalent of component B) is used. A range of 0.01 to 0.7 equivalents, particularly 0.4 to 0.7 equivalents of component C) relative to the equivalent amount improves releasability, printability, coating suitability, curability,
This is preferable in terms of harmonizing the properties of the cured film.

There is some degree of discretion in the method of reacting the above three components.

In the first embodiment, an excess of organic polyisocyanate is reacted with organopolysiloxane to form a prepolymer having free isocyanate groups at both ends. At this time, the chain length of the prepolymer can be changed by changing the quantitative ratio of organopolysiloxane and polyisocyanate. Next, an acrylate compound is added to both ends of the prepolymer obtained above. In a second embodiment, an organic polyisocyanate and an acrylate compound are first reacted to produce a compound having a free isocyanate group at least at one end, and then further reacted with an organopolysiloxane.

In either embodiment, the above reactions proceed without a catalyst, but a catalyst can be used to accelerate the reaction. Such catalysts include dibutyltin dilaurate, stannous octoate, dioctyltin diacetate, morpholine, triethylenediamine, and the like. These catalysts can be used, for example, in a proportion of 0.01 to 1.0%, based on the total weight of the reaction mixture.

The stripping treatment agent of the present invention can use the above reaction product alone or in a mixture with other reactive monomers, solvents, pigments, fillers and other additives. As the reactive monomer, an acrylate monomer having an unsaturated bond or a vinyl or allyl group-containing monomer is used, for example, in an amount of about 5 to 100 parts per 100 parts of the above reaction product.

An example of the use of the releasable treatment agent of the present invention will be explained with reference to the accompanying drawings. As shown in a cross-sectional view in FIG. Preferably, the releasable treatment agent obtained as described above is
Apply at a rate of 0.1 to 5 g/m ² (solid content). If the coating amount is less than 0.1 g/m ² , the unevenness on the surface of the substrate will not be completely flattened, and therefore sufficient releasability will not be obtained. Moreover, even if it is applied in an amount exceeding 5 g/m ² , no further improvement in releasability can be expected and it becomes uneconomical. The coating method is arbitrary depending on the base material, and for example, roll coating, gravure coating, air knife coating, curtain flow coating, etc. are used. When coating a paper base material without a sealing layer, a release agent layer that hardly penetrates into the base material can be obtained by using a solvent-free release agent and hot-melt coating. In terms of coating suitability, it is desirable that the viscosity at the time of coating be 10,000 centistokes or less, and if necessary, the viscosity can be adjusted by adjusting the molecular weight of the above reaction product or diluting it with a reactive monomer as appropriate. .

After the releasable treatment agent 2 of the present invention is applied as described above, it is irradiated with ionizing radiation such as electron beams, gamma rays, X-rays, and short wavelength ultraviolet rays to be cured. For example, for electron beams, Kotscroft-Walton type,
Emitted from various electron beam accelerators such as Van de Graaff type, resonant transformer type, linear type, dynamitron type, high frequency type, etc., it is 50 to 1000 KeV, preferably 100 to
An electron beam with an energy in the range of 300 KeV is used. Appropriate irradiation dose is about 0.5 to 10 Mrad.

Next, as shown in FIG. 2, on the release agent layer 2a obtained by curing, a printing pattern 3 is applied with ordinary oil-based or water-based ink as necessary,
A label roll as shown in FIG. 3 is obtained by forming an adhesive layer 4 on the back surface, making perforations 5 and winding it up. Further, as shown in FIG. 4, it is also possible to obtain a laminate of forms 6 with one end fixed with an adhesive 4. The label or form thus obtained has the feature that printing or writing can be easily done with not only oil-based ink but also water-based ink in the margin provided by the surface of the release agent 2a.

As described above, according to the present invention, the sealing layer is made of a reaction product of an organopolysiloxane having a polyether moiety, an organic polyisocyanate, and an acrylate compound having an active hydrogen-containing group, and is easily made into a solvent-free type. It is easy to coat even on paper without paper, and cures quickly by irradiation with ionizing radiation to provide a release agent layer with good releasability and good printability even with water-based inks. A treatment agent is provided.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Hydroxyethyl acrylate was added dropwise to a mixture of tolylene diisocyanate and 10% ethyl acetate while maintaining the temperature of the reaction system at 40 to 60°C. After the addition was completed, stirring was continued for 2 hours to obtain an adduct of tolylene diisocyanate and hydroxyethyl acrylate.

The adduct obtained above was added in equimolar amounts to the following organopolysiloxane having a polyether bond.

About 0.1% of the total amount of di-n-butyltin diurarate was added to this mixture as a catalyst, and the mixture was stirred for 3 hours while maintaining the temperature at 50 to 60°C to cause a reaction.

The release treatment agent of the present invention obtained by adding 0.01% of hydroquinone to the reaction product obtained above was coated in an amount of 0.5 g on high-quality paper (55 kg manufactured by Daishowa Paper Co., Ltd.) by a roll coating method. / ^m2 , and then using an electron beam irradiation device (manufactured by ESI, Electro Curtain CB200/50/30)
was used to cure the material by irradiating it with an electron beam under the conditions of an accelerating voltage of 175 KV and an irradiation dose of 1 Mrad. Further, as shown in FIG. 2, an acrylic pressure-sensitive adhesive (BPS2411 manufactured by Toyo Ink Co., Ltd.) was applied in a striped manner to the surface opposite to the surface to which the release agent was applied in an amount of 10 g/m ² . After this, when printing was performed on the peeled surface using an ink containing a polyether binder as the main component, the print was clear and the peeling force against the adhesive (180° peeling, 30cm/min A good result was obtained with a tensile speed of 10 g/cm. Further, although unwinding was carried out at a pulling speed of 100 m/min, no damage to the base material such as paper flakes occurred.

Example 2 While keeping a mixture of tolylene diisocyanate and 10% ethyl acetate at 50 to 60°C, about 0.1% of the total amount of catalytic dilaurin was added to the following silicone at a ratio of 0.5 mol to 1 mol of tolylene diisocyanate. A di-n-butyltin acid solution was added dropwise.

After the dropwise addition, stirring was continued for 3 hours to obtain a prepolymer having isocyanate groups at both ends. Then, for 1 mole of the above prepolymer, 2
Drop moles of hydroxyethyl acrylate,
Stirring was continued for 3 hours while maintaining the temperature at 50-60°C. 0.01 for the total amount of reaction products thus obtained.
% hydroquinone was added.

When the obtained release agent was coated in the same manner as in Example 1 and the writability and releasability were evaluated, good results were obtained.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic cross-sectional views in the thickness direction of a base material showing the process of applying the releasable treatment agent of the present invention to the base material, and FIGS. 3 and 4 illustrate the releasable treatment obtained, respectively. 1 is a conceptual perspective view of a product having a surface; FIG. DESCRIPTION OF SYMBOLS 1...Base material, 2...Peelable treatment agent layer (2a...its cured state), 3...Normal printed pattern, 4...Adhesive layer, 5
...Perforation, 6...Form.

Claims (1)

[Claims] 1 For 1 equivalent of isocyanate of component B),
C) 0.01 to 0.7 equivalent of active hydrogen of component and A)
Total amount of active hydrogen of component OH and C) component 0.8
It consists of a urethane-modified organopolysiloxane containing a terminal unsaturated group, which is a substantially complete reaction product between the following components A), B) and C), and is characterized by having printability. Ionizing radiation curing type peeling treatment agent. A Organopolysiloxane represented by the following general formula (1) However, here, R ¹ and R ² are each a methyl, ethyl, propyl or trifluoropropyl group, x and y are each a positive number; m is an integer of 0 to 4; n is 2 to 3
B an organic polyisocyanate, and C an acrylate compound having at least one active hydrogen-containing group selected from a hydroxyl group, a carboxyl group, and an amino group in one molecule.