JPS5911628B2 - Composition for forming a peelable film - Google Patents

Description

[Detailed description of the invention] The present invention relates to a composition for forming a peelable film.

Specifically, the present invention relates to a composition for forming a releasable film that has poor printing properties, stable releasability against adhesive substances, and has a low slip property of 10. Conventionally, curable organopolysiloxane compositions have often been used to impart releasability from adhesive substances by forming a cured film on the surface of various substrates such as various papers, synthetic resin films, fibers, and aluminum15. Are known.

These organopolysiloxane compositions include those whose curing mechanism is based on a condensation reaction (Japanese Patent Publication No. 35-13709, Japanese Patent Publication No. 36-1397, etc.) and those based on an addition reaction (Japanese Patent Publication No. 46-26798, etc.). is proposed. However, although these have excellent releasability, they have poor printing properties.In other words, when producing adhesive sheets or adhesive tapes, the organopolymer opening 25
The xane composition had disadvantages such as poor printing properties on the coated surface, repelling printing ink and marker ink, and poor printing and writing ability.

Usually, adhesive sheets and adhesive tapes are often wound into rolls for their purpose, and therefore the organopolysiloxane composition on the opposite side of the adhesive layer of the sheet or tape base material 30 to which the adhesive is applied The release layer to which the product is applied is superimposed and adjoins. This also applies to the case 35 in which the organopolyloxane composition is coated on a sheet or tape base material and an adhesive is coated thereon. Adhesive sheets like this are often used by printing, etc.
Conventionally, since the printability on the surface of the release layer was poor, it was necessary to dispose a high-quality paper or the like with excellent printability between the adhesive layer and the back surface of the sheet base material. Furthermore, when adhesive tape is used to package cardboard, etc., it is not possible to write the recipient's address on the tape. As a result of intensive research by the present inventors in order to improve the above-mentioned drawbacks, we found that, in particular, it has excellent printing performance and residual adhesion rate, has stable releasability against adhesive substances, and has a peelable material with low slipperiness. This led to the invention of a composition for forming a sexual film.

That is, the present invention consists of (1) 100 parts by weight of a substantially linear organopolysiloxane having a viscosity of 1000 centipoise or more at 25°C and a hydroxyl group at the end of the molecular chain; (2) finely powdered silica;
5 to 80 parts by weight (3) General formula (in the formula,
R1 and R2 are monovalent hydrocarbon groups of which at least 25 mole percent are phenyl groups.

phenyl group-containing organosilane or organopolysiloxane (n represents a number from 1 to 100) 2
~40 parts by weight (4) At least 3 Si in 1 molecule
Organohydrodiene polysiloxane with H group 0
．． The present invention relates to a composition for forming a peelable film, comprising 5 to 40 parts by weight of (5) a catalytic amount of an organic acid metal salt, and (6) an arbitrary amount of an organic solvent.

To explain in detail each component used in the present invention, component (1
) is a substantially linear organopolysiloxane group; ,
It is preferably an allyl group, a phenyl group, a 3,3,3-trifluoropropyl group, etc., of which at least 80 mol% is a methyl group.

) and has a viscosity ranging from 1000 centipoise or more to polymerizable gum at 25°C, and
It contains a hydroxyl group at the end of the molecular chain. Hydroxyl groups may also be present in the molecular chain in addition to the terminals of the molecular chain. The term "substantially linear" means a straight chain or a straight chain having a partially branched portion. Component (1) can also be used in combination of two or more thereof. The fine powder silica of component (2) may be produced by either a dry method or a wet method, and there are no limitations on the particle size.

However, from the viewpoint of printability when used in combination with the next component (3), it is preferable to use only wet silica or a combination of wet silica and dry silica. This fine powder silica has the effect of improving the strength of the cured film and reducing slipperiness compared to conventional organopolysiloxane compositions.
However, when component (2) is added alone, it has almost no effect on printing properties, but when used in combination with component (3) described below, printing properties can be dramatically improved. General formula of component (3) (wherein R1 and R2 are -valent hydrocarbon groups, such as methyl group, ethyl group, propyl group, phenyl group, vinyl group, allyl group, 3,3,3-trifluoro Examples include propyl groups, of which at least 25 moles are present.

n represents a number from 1 to 100. ) is a phenyl group-containing organosilane or organopolysiloxane. Examples of this include diphenylsilanediol,
Methyl phenyl silane diol, vinyl phenyl silane diol, C'. W,. Egg God Ra゜kiji 2! Dihydroxy-diphenylpolysiloxane, α,ω-dihydroxy-methylphenylpolysiloxane, has hydroxyl groups at both ends of the molecular chain.

Dimethylsiloxane/diphenylsiloxane copolymer,
Dimethylsiloxane/methylphenylsiloxane copolymer, dimethylsiloxane/methylphenylsiloxane/
Examples include organopolysiloxanes such as methylvinylsiloxane copolymer and dimethylsiloxane/methylphenylsiloxane/methyl(3,3,3-trifluoropropyl)siloxane copolymer. Component (3) has no effect on printability when added alone, but when used in combination with component (2), it dramatically improves printability, which was considered impossible with conventional releasable organopolysiloxane compositions. You can print and write clearly without repelling printing ink or magic ink.

Moreover, the coating property to the substrate and the adhesive strength of the pressure-sensitive adhesive do not decrease, and a stable composition for forming a releasable film with no change in releasability over time can be obtained. In order to have these effects sufficiently, component (1) organopolysiloxane 10
For each 0 parts by weight, 5 to 80 parts by weight of finely powdered silica as component (2) and 2 to 40 parts by weight of phenyl group-containing organosilane or organopolysiloxane as component (3) are required. If component (2) is 5 parts by weight or less and component (3) is 2 parts by weight or less, the effect on printability will be halved;
This is because if component (3) exceeds 80 parts by weight, it becomes difficult to knead with organopolysiloxane, and if component (3) exceeds 40 parts by weight, coatability to substrates and curability decrease. Furthermore, if the phenyl group in component (3) is less than 25 mol %, the printability effect will be lowered, making it impossible to fully satisfy the object of the present invention. The organohydrodiene polysiloxane containing at least three SlH groups in one molecule of component (4) is component (1).
This is a crosslinking agent for forming a cured film through a condensation reaction with the hydroxyl groups of

A typical example thereof is methylhydrogenpolysiloxane, which includes tetramethyltetrahydrogencyclotetrasoloxane, methylhydrogenpolysiloxane, and a copolymer of methylhydrogensiloxane and dimethylsiloxane. However, it is not limited to this, and may contain an alkyl group other than a methyl group or a phenyl group. Also,
The degree of polymerization is 2 or more and is allowed up to a polymerizable degree. Considering the formation of a cured film and peeling performance, the amount of component (4) added is usually 100% of component (1).
The range is from 0.5 to 40 parts by weight. The organic acid metal salt of component (5) may be used as a catalyst for the conventionally known condensation reaction between a hydroxyl group bonded to a silicon atom and a hydrogen atom bonded to a silicon atom, and examples of the metal include tin, zinc, lead, and iron. Specific examples include dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dioctyltin dilaurate, tin octoate, zinc naphthoate, and iron octoate.

The amount of the organic acid metal salt to be used may be any amount sufficient to cure the present composition, and the amount to be added can be arbitrarily selected depending on processing conditions and the like. The organic solvent of component (6) may be any organic solvent as long as it can dissolve the organopolysiloxane of component (1), and includes aromatic hydrocarbons such as benzene, toluene, and xylene, and aliphatic hydrocarbons such as heptane, hexane, and pentane. Examples include hydrocarbons, halogenated hydrocarbons such as trichlorethylene and perchlorethylene, ethyl acetate, and methyl ethyl ketone. The organic solvent is used to dilute the composition of the present invention so that it can be applied uniformly to the curtain material, and the amount used is not specified because it varies greatly depending on the viscosity of the composition. The composition of the present invention comprises components (1} to
It is obtained by simply uniformly mixing, dissolving and dispersing component (6), and there is no particular restriction on the order of addition of each component.

However, the mixing method is to first knead component (1), component (2), and component (3) under heat (in some cases, heat treatment after kneading), and then mix them together with the remaining components. Preferably, it is dissolved in a solvent. The composition for forming a peelable film of the present invention may be used as it is, or may be used by adding an organopolysiloxane resin soluble in an organic solvent, a condensation reaction retarder, a pigment, a hydrocarbon polymer substance, etc. You may.

The composition for forming a peelable film of the present invention forms a cured film with excellent adhesion on the surface of various substrates such as various papers, synthetic resin films, fibers, and aluminum. It has a major feature of excellent printability with printing ink, magic ink, etc., which is not seen in cured films of polysiloxane compositions.

Furthermore, since the slipperiness is lower than that of conventional products, there is an advantage that even when release papers coated with the present composition are stacked, the stacks are less likely to collapse. On the other hand, for adhesive substances, the residual adhesion rate is excellent, peeling is moderately easy, and it is very stable without changing over time. Furthermore, it has the advantage that the change in releasability due to the amount of coating is small, and the coatability to the above-mentioned curtain materials is excellent, so that the amount of coating can be reduced. When printing is required on an adhesive sheet or tape, conventional adhesive sheets or tapes require a laminate paper for the printed side in addition to release paper and adhesive, but release paper coated with the composition of the present invention can be used. The adhesive sheet or tape used may be a combination of release paper and adhesive;
Costs are greatly reduced because the laminate paper can be omitted.
Next, examples of the present invention will be described, where parts mean parts by weight and viscosity is the value at 25°C.

Moreover, peel resistance, residual adhesion rate, and printability were measured under the following conditions. [Peel resistance] Coating a predetermined amount of the composition of the present invention on the surface of a sheet-like base material,
After forming a cured film at a predetermined temperature and for a predetermined time, Olivine BPS 5l27 manufactured by Toyo Ink Mfg. Co., Ltd. as an acrylic adhesive or Olivine BPS 24ll manufactured by Toyo Ink Manufacturing Co., Ltd. as a rubber adhesive was applied to the surface of the film and cured at 70°C for 2 hours.
Heat for 1 minute.

Next, the laminated papers are pasted together and aged at 25° C. under a load of 20 g/d for a predetermined period of time (1 day and 60 days in this example). The aged sample was cut into 5-width pieces and tested at an angle of 180°C for 3 times using a tensile tester.
The laminated paper is pulled at a speed of 0 Cfn/min and the force (f!) required for peeling is measured. [Residual adhesion rate] As in the case of peel resistance, a cured film is formed on the surface of the sheet-like base material, and Nitto Polyester Tape 31B manufactured by Nitto Electric Industry Co., Ltd. is laminated on the surface.

After that, a load of 209/CF7l was placed on it, and after heat treatment at 70°C for 20 hours, the tape was removed and attached to a stainless steel plate. This processing tape was made from a stainless steel plate, 18
30CT at 0° angle! The force (f) required for peeling at a rate of L/min is measured and expressed as a percentage of the force (9) required to peel an untreated standard tape from a stainless steel plate. [Printability] As in the case of peel resistance, a cured film is formed on the surface of the sheet-like base material, and characters are written on the surface with oil-based magic ink, and judged by whether the characters can be written clearly.

Example 1 100 parts of α,ω-dihydroxy-dimethylpolysiloxane with a viscosity of 10,000 centipoise, 20 parts of fume silica (dry silica) with BET2OOm2/g as fine powder silica, 20 parts of wet silica with D&A adsorption of 240η MOlAC-9 and diphenyl. 12 parts of silane diol were mixed and kneaded while heating at 180° C. for 2 hours.

To this, 5 parts of methylhydrodiene polysiloxane having a viscosity of 20 centipoise and having trimethylsilyl groups blocked at both ends of the molecular chain was added, and 2983 parts of toluene were added and mixed.
After dissolving and dispersing, 4 parts of dibutyltin diacetate was added and thoroughly mixed to obtain a composition of the present invention. Next, as Comparative Example 1, 15 parts of D,ω-dihydroxy-dimethylpolysiloxane with an average degree of polymerization of 15 and 29 parts of toluene were used instead of 12 parts of diphenylsilanediol in the above composition.
A composition was prepared under the same conditions as above except that 3040 parts were added instead of 83 parts.

As Comparative Example 2, fine powder silica and phenylsilanediol were removed from the composition of the present invention, and the amount of toluene added was 19.
A composition was prepared under the same conditions as above except that the amount was 95 parts. As Comparative Example 3, a composition was prepared under the same conditions as above except that only the finely powdered silica was removed from the composition of the present invention and the amount of toluene added was 2223 parts. These compositions were examined for peel resistance, residual adhesion rate, and printability using the methods described above.

The conditions were to coat polyethylene-laminated kraft paper with a solid content of 0.59/1n' at 150°C.
A cured film was formed by heat treatment for 0 seconds, and for peel resistance, Olivine BPS24ll manufactured by Toyo Ink Mfg. Co., Ltd. was used as an adhesive. The test results of Examples and Comparative Examples are shown in Table 1. The present invention did not repel the magic ink at all, and the characters could be written evenly and neatly, and the printing performance was very good. Moreover, both peel resistance and residual adhesion rate were good. On the other hand, in Comparative Examples 1 to 3, the repellency of the magic ink was remarkable, and the letters were blurred and could not be written clearly. Example 2 100 parts of dimethylpolysiloxane raw rubber having hydroxyl groups at both ends, D&A adsorption 240W9m as fine powder silica
30 parts of wet silica at 0 V, α, ω- with an average degree of polymerization of 10
15 parts of dihydroxy-methylphenyl polysiloxane (phenyl group content: 50 mol %) were kneaded while heating at 180° C. for 2 hours.

To this, 8 parts of a dimethylsiloxane/methylhydrogensiloxane copolymer with a viscosity of 6 centipoise and both ends of the molecular chain blocked by trimethylsilyl groups and 2755 parts of toluene were mixed, dissolved, and dispersed, and then 6 parts of dibutyltin dioctoate was added and mixed. A composition of the invention was prepared. Next, as Comparative Example 4, in place of 15 parts of α,ω-dihydroxy-methylphenylpolysiloxane (phenyl group content: 50 mol%) of the above composition, 1 part of the average polymerization degree used in Comparative Example 1 was used.
5 D,ω-dihydroxy-dimethylpolysiloxane 1
A composition was prepared under the same conditions as above except that 5 parts were added.

In addition, as Comparative Example 5, the above phenyl group content was also 5.
Instead of 0 mol% D, ω-dihydroxy-methylphenyl polysiloxane, α, ω-dihydroxy-dimethylsiloxane/methylphenylsiloxane copolymer (phenyl group content 5 mol%) with an average degree of polymerization of 20 15 A composite was prepared under the same conditions as above, except that As Comparative Example 6, fine powder silica and α,ω-
A composition was prepared under the same conditions as above except that dihydroxy-methylphenyl polysiloxane was removed and the amount of toluene added was 2052 parts. These compositions were coated on glassine paper at a concentration of 0.9g/ml in terms of solid content, and
For those that have been heat treated for seconds to form a hardened film,
Peel resistance, residual adhesion rate, and printability were investigated.

The adhesive used for peel resistance was manufactured by Toyo Ink Manufacturing (
Olivine BPS5l27 manufactured by Co., Ltd. was used. The results are shown in Table 2, and the printing of the present invention did not repel the magic ink at all, and the characters could be written evenly and neatly, and the printing performance was very good.

In addition, it exhibited stable peel resistance and an excellent residual adhesion rate. On the other hand, in Comparative Examples 4 to 6, the peel resistance and residual adhesion rate were good, but the repellency of the magic ink was significant and the printing performance was very poor. Although it was observed that Comparative Example 5 had improved printing performance compared to Comparative Examples 4 and 6,
This was worse than the present invention and was not practical. Example 3 Dimethylsiloxane/methylphenylsiloxane copolymer raw rubber having hydroxyl groups at both ends (phenyl group content: 5
mol%) 100 parts, BET3OOm as fine powder silica
2/9 fuyum silica (dry silica) 10 parts, D&A
50 parts of wet silica with an adsorption average of 240 ηMOV and 20 parts of α,ω-dihydroxy-methylphenylsiloxane/diphenylsiloxane copolymer (phenyl group content 75 mol%) with an average degree of polymerization of 20 were heated at 180°C for 2 hours. While kneading.

Claims (1)

[Scope of Claims] 1 (1) 100 parts by weight of a substantially linear organopolysiloxane having a viscosity of 1000 centipoise or more at 25°C and a hydroxyl group at the end of the molecular chain (2) 5 to 80 parts by weight of finely powdered silica (3) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R^1 and R^2 are monovalent hydrocarbon groups,
At least 25 mol% of them are phenyl groups. phenyl group-containing organosilane or organopolysiloxane (n represents a number from 1 to 100)
40 parts by weight (4) 0.5 organohydrodiene polysiloxane having at least 3 SiH groups in one molecule
A composition for forming a peelable film, comprising: (5) a catalytic amount of an organic acid metal salt, and (6) an arbitrary amount of an organic solvent. 2. The composition according to claim 1, wherein the finely powdered silica of component (2) is wet silica. 3. The composition according to claim 1, wherein the finely powdered silica of component (2) is a mixture of wet silica and dry silica.