FI92597C - Organopolysiloxane composition for use in release liners - Google Patents

Description

92597

Organopolysiloxane composition for use in release liners

The present invention relates to an organopolysiloxane composition for use in the coating of release paper, and in particular to an organopolysiloxane composition for use in the production of release paper, which can be rapidly cured by heating or irradiating by ultraviolet.

Among the many different types of organopolysiloxane compositions previously used for baling release paper, the most commonly used type is 15 ns. addition reaction type compositions consisting of an organopolysiloxane containing an alkenyl group, an organohydrogenpolysiloxane and a platinum catalyst which promotes the addition of silicon-linked alkenyl groups and silicon-related hydrogen atoms of the essential constituents. One problem with this type of organopolysiloxane composition is that the hardenability and surface peelability of the peeled release paper are greatly affected by several hours of standing or prolonged standing of the pre-blended peeling composition.

Platinum-containing organopolysiloxane compositions containing an addition reaction type for baling release paper are classified as those that can be cured by heating at 100 ° C or by irradiation with ultraviolet radiation. Although compositions of the ultraviolet-curable type can be rapidly cured by non-irradiated UV light even at room temperature or relatively low temperature, even when heating is necessary, • · 92597 2 in the låmp5 mode, after mixing the boiler and the releasability of the release paper coated thereon, the mouth-grate varies after curing. A proposal to this effect is made in JP-A-61-235 461, according to which the composition is formed using a large excess of organohydrogenpolysiloxane in excess of that required to cure the alkenyl group-containing organopolysiloxane. Although the stability of the premixed composition, i.e. the "pot life", can be improved in this way, such a large excess of organohydrogenpolysiloxane composition has poor performance due to the need to detach the coated release liner. In particular, the peeling resistance of the release paper is greatly increased when the release paper applied to a sticky or adhesive surface and attached is stored for a long time.

The present invention thus relates to a new improved oropol 20 silopolysiloxane composition for use in the release paper coating, which has a considerably improved pot life, i.e. an improved cure stability after mixing of the catalyst.

Thus, the organopolysiloxane coosage-25 turnus to be used for coating the release paper according to the present invention contains: (A) 100 parts by weight of an organopolysiloxane having alkenyl groups attached to silicon atoms, (B) 0.1 to 10 parts by weight of organol, at least 20 silicon atoms in 30 molecules and at least three hydrogen atoms directly attached to the silicon atoms of the molecule, (C) a catalytic amount of a platinum compound, and (D) 0.1 to 10, preferably 3 to 10 parts by weight of an organosilane compound or an organopolysilane up to six silicon atoms and at least one hydrogen atom directly attached to the silicon atom.

3,92597

The organopolysiloxane coefficient defined above may be cured by heating, but if curing of the composition by UV radiation is desired, the composition may optionally further comprise (E) a photosensitizer compound in an amount of, for example, up to 10 parts by weight of component (A) 100 parts by weight. towards.

From the above description, it can be understood that the most typical ingredient of the organopolysiloxane composition of the invention is component (D) with other component pathways being conventional. Due to this unique ingredient, the cure of the organopolysiloxane coating liquid according to the invention remains good and does not remain in the vessel for four hours or more after standing at room temperature. The release capacity of the release paper coated with the organopolysiloxane composition according to the invention is also not adversely affected, even when the release paper has been prepared with the aid of the invention according to the invention. the peelability of the release paper. The organopolysiloxane composition according to the invention is furthermore advantageous because the adhesion of its coating layer to various substrate materials is good. Of course, the addition of component (D) does not have a detrimental effect on the curing of the composition by light when the composition is converted to light cure by adding to it component (E) 30 a photosensitizer.

The basic component of the organopolysiloxane composition of the invention, component (A), is an alkopolyl-containing organopolysiloxane having at least two silicon-bonded alkenyl groups in the molecule to cure the composition. The organopolysiloxane may be, without limitation, either straight or branched, cyclic or reticulated, preferably straight chain. Its degree of polymerization is not limiting. The alkenyl groups attached to the silicon atoms of the organopolysiloxane molecules can be selected from the following: a vinyl group, an allyl group, an isopropenyl group, a butenyl group and the like, of which a vinyl group is preferable. Organic groups attached to the silicon atoms of the organopolysiloxane in addition to alkenyl groups are monovalent hydrocarbon groups such as alkyl groups, e.g. methyl, ethyl, propyl, butyl or octyl, aryl groups, e.g. phenyl or tolyl or arallyl groups, e.g. 2-phenyl or e.g. -phenylpropyl as well as mybs substituted monovalent hydrocarbon groups obtained by replacing some or all of the hydrogen atoms in the 15 hydrocarbon groups listed above with substituents such as halogen atoms; Examples are chloromethyl, 3-chloropropyl and 3,3,3-trifluoropropyl.

In particular, esimerkkejM organopolysiloxanes of component (A) include dimethylpolysiloxanes with 20 paSteryhminå is dimetyylivinyylisilyyliryhmia, dimethylpolysiloxanes whose end groups have dimethylallyl-silyl group, the poly (diorganosiloxane), the composition for the VAT difenyylisiloksaaniyksik5ista and dimethylsiloxane-yksikdistå and whose end groups have fenyylimetyylivinyy-25 lisilyyliryhmiå, poly ( diorganosiloxane) consisting metyylivinyylisiloksaaniyksikoista and dimethyl loksaaniyksikdista and whose end groups is a trimethyl-silyl group, the poly (diorganosiloxane) consisting metyylivinyylisiloksaaniyksikbistå and dimethylsiloxane-30 niyksikbistå and which has a silanol end groups, a poly (diorganosiloxane) consisting metyylivinyy-lisiloksaaniyksikQista and dimethylsiloxane unit and having a terminal group S of dimethylvinylsilyl groups, poly (methyl-3,3,3-trifluoropropylsiloxanes) having 35 end groups as dimethylvinyl lyyl groups, vinyl poly (silsesquioxanes), copolymeric organopolysiloxanes consisting of monofunctional dimethyl vinylsiloxy units and tetrafunctional SiO 2 units and the like.

The component (B) of the organopolysiloxane composition 5 according to the invention, which acts as a crosslinking agent for the component (A) described above, is an organohydrogenpolysiloxane having at least three hydrogen atoms in the molecule, preferably directly attached to the silicon atom. The organohydrogenpolysiloxane consists of siloxane units which are organohydrogensiloxane units and / or hydrogen siloxane units, either alone or optionally together with other types of organosiloxane units which do not have silicon-related hydrogen atoms. The molecular structure of the organopolysiloxane may be straight or branched chain, cyclic or reticulated without any particular limitation. The organopolysiloxane molecule should have at least 10 or more preferably at least 20 silicon atoms in order to be volatile.

20 Specific examples of organopolysiloxanes suitable as component (B) include copolymeric poly (dimethylsiloxane-methylhydrogensiloxanes) having dimethylhydrogensilylmethylsilylsilylsilane, copolymeric poly (dimethylsiloxane-methylsiloxane), -methylhydrogensiloxanes) having dimethylphenylsilyl groups at their terminals, poly (methylhydrogensiloxanes) having trimethylsilyl groups at their terminals, etc. Component (B) is present in an amount of organopolysiloxane containing an alkenyl group as (A). When the amount of component (B) is too small, complete curing of the composition is hardly obtained even by heating or UV irradiation. On the other hand, when its amount is too large, the peeling capacity of the release paper produced therein is somewhat reduced, and the peeling resistance of the paper is high.

Component (C) in the organopoly-siloxane composition of the invention is a platinum compound which acts as a catalyst to promote the reaction between the silicon-linked alkenyl groups of component (A) and the silicon-related hydrogen atoms of component (B). The platinum compound is preferably chloroplatinic acid, unmodified or modified with an alcohol or a complex thereof with an olefin 10 or a vinylsiloxane compound, although platinum may also be used in elemental form such as platinum black or on a solid support (e.g. , although less favorably. Instead of platinum, palladium and rhodium can be used for this purpose. The most preferred catalyst is a complex obtained by the reaction between chloroplatinic acid and an organopolysiloxane containing a vinyl group. The platinum catalyst is included in the organopolysiloxane composition of the invention in a catalytic amount which is not particularly limiting due to the desired curing rate. Roughly defined, the amount of platinum catalyst is 1-1,000 parts by weight of platinum per million parts by weight (ppm) of components (A) and (B).

As an optional ingredient, the organic polysiloxane composition of the invention is mixed with an addition retarder, if desired. Examples of such reaction retarders are known acetylene compounds, e.g. 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-butyn-3-30 ol, 3-methyl-3-pentynyl-1-yne, 3-methyl-1-penty-3-ol, 5-methyl-3-hexyn-1-yne and the like, nitrogen-containing organic compounds, phosphorus-containing organic compounds and oxime compounds. When the reaction retarders are added, they amount to 0.1 to 10% by weight of the weight of component (A) in the organopolysiloxane-35 composition according to the invention.

92597 7

The fourth essential ingredient, i.e. component (D), the organopolysiloxane composition of the invention is an organosilane or organopolysiloxane compound having at least one hydrogen atom in the molecule directly attached to a silicon atom. It is essential that the boiling point of the component (D) compound is relatively low, for example 250 ° C or lower at normal pressure. Therefore, the organosilicon compound (component D) should contain at most six silicon atoms in the molecule. Examples of organo-10 silane and organopolysiloxane compounds suitable as component (D) are methyldimethoxysilane, b.p. 61 ° C, methyldiethoxysilane, b.p. 94 ° C, trimethoxysilane, b.p. 85 ° C, triethoxysilane, b.p. 131 ° C, 1,1,3,3-tetramethyldisiloxane, b.p. 70.5 ° C, pentamethyldis-15 oxane, b.p. 85 ° C, 1,1,1,3,5,5,5-heptamethyltrisiloxane, b.p. 141 ° C, 1,3,5,7-tetramethylcyclotetrasiloxane, b.p. 134 ° C, 1,3,5,7,9-pentamethylcyclopentasiloxane, b.p. 169 ° C, 1,1,1,3,5,7,9,9,9-nonamethylpentasiloxane, b.p. 215 ° C and others Higher poly (methylhydrogensiloxanes), such as compounds of the formula Me 2 Si-O-fSiHMe-Of ^ SiMe 3 (Me is a methyl group and n is an integer of 5 or more) boiling in the IMmpd state above 250 ° C , non-vMt are not preferred. The amount of these compounds used in the organopolysiloxane composition according to the invention is usually 0.1 to 10 parts by weight, preferably 3.0 to ♦ 10.0 parts by weight per 100 parts by weight of component (A).

Of course, when the amount of addition is too small, the desired improvement is not achieved. On the other hand, when its addition amount is increased above said upper limit, the stability of the composition is no longer improved, instead, the peelability of the paper coated with the composition is deteriorated.

Components (A), (B), (C) and (D) described above are essential ingredients of the organopolysiloxane composition of the invention when curing the composition is performed by heating. When it is desired to cure the composition by UV irradiation, the composition should additionally contain 8,92597 of the photosensitizer compound as component (E). As the component (E), various known compounds commonly used as photosensitizers can be used, for example, the following: acetophenone, propiophenone, benzophenone 5, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, carbazole, 3-methylacetone, 3-methylacetone -benzophenone, 4-ethylbenzophenone, 4-hydroxybenzophenone, benzoin ethyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-diethoxyacetophenone and the like, of which 4-methylbenzophenone is preferred, -methoxybenzophenone, 4-hydroxybenzophenone and 2-hydroxy-2-methyl-1-phenylpropan-1-one. As mentioned above, this component (E) is not essential when the curing of the composition is carried out by heating, but in its amount, the composition according to the invention should contain 0.1 part by weight of vShintaSn per 100 parts by weight of component (A) when the composition is mus is cured by UV rain. Its amount should not exceed 10 parts by weight per 100 parts by weight of component (A), because too much of it affects the ability of the compound to absorb UV light energy and impairs its efficiency and has some detrimental effect on the composition coated with the composition. paper peelability. The preferred amount of the photosensitizer compound in the composition is 2.0 to 6.0 parts by weight per 100 parts by weight of the component (A).

The organopolysiloxane composition for coating the release paper according to the invention can be prepared by mixing the essential components described above into a uniform mixture, if desired together with the optional ingredients. Depending on its intended use, a small amount of an inert filler such as titanium dioxide and dimethylpolysiloxane, which is unreacted, may be mixed with the composition of the invention, depending on its intended use. The viscosity or consistency of the composition to be used for coating the release paper thus prepared is not particularly limiting, but depends on the desired coating thickness and the coating machine ♦ 92597 9 used. The viscosity of the roughly defined composition should be 10 to 100,000 cP at 25 ° C, preferably 200 to 2,000 cP at 25 ° C, especially when the composition is used as such without dilution with an organic solvent to facilitate coating. When the viscosity of the composition as such is too high, it may be mixed with an organic solvent to reduce the viscosity, if desired. Examples of organic solvents include toluene, xylene, hexane, heptane, mineral spirit, trichlorethylene, tetrahydrofuran, methyl ethyl ketone, ethyl acetate and the like.

Without the component used as the photosensitizer compound, the organopolysiloxane composition of the present invention applied to the surface of the substrate, such as paper, can be cured by heating, for example, at 50 to 100 ° C for a few seconds to 10 seconds or longer, When component (E) is mixed into the composition as a photosensitizer compound, the curing of the composition can be performed by non-irradiated UV light.Suitable UV light sources include Xenon lamps, low, medium and high pressure etc., where the quality of the lamp is not particularly limiting When the composition is diluted with an organic solvent, prior to UV irradiation of the coating film, heating treatment is preferably performed to obtain a solvent completely removed from the coating film.

The following are examples to illustrate in detail the organopolysiloxane-30 composition used for coating the release paper of the present invention. In the following description, the term "parts" always means "parts by weight" and the viscosity values are values measured at 25 ° C. The hardening of the coating film and the peeling resistance of the release paper in the examples were evaluated by the methods described below.

92597 10

curability:

The film or sheet used as a substrate was coated with the coating composition using a specified amount of coating, and the coated film or sheet 5 was subjected to the curing process described in each case, for example. The thus-cured film of the organopolysiloxane composition on the surface of the substrate was lightly rubbed with a fingertip to examine the damage to the coating layer or to reduce the opacity of the coating layer. good curing, with little damage and opacity in the bale film, and C = poor curing, 15 with a lot of damage and very opacity in the coating film.

Peeling resistance ϊ

The film or sheet used as a substrate was baled with the coating composition using a defined coating size, and the baled film or sheet was subjected to the curing process described in each example. Then, a solvent-type pressure-sensitive acrylic adhesive (Oribibe .BPS-8170, manufactured by Toyo Ink Manufacturing

Co.) was applied to the film and heated at 100 ° C for three minutes, after which a sheet of wrapping paper (40 g / m 2) was placed on the film 2 and bound and the 2 sheets were kept under a weight of 20 g / cm m for a specified time at 25 ° C. . The test sheet prepared by NS was cut into 5 cm wide strips, which were subjected to a peeling resistance measurement in grams between the baled film or sheet and the coating paper by pulling in a tensile strength device in the direction of 180 ° at a speed of 30 cm / min.

Example 1

Three solvent-type coating compositions of 35, hereinafter referred to as Sample No. 1, No. 2 and No. 3, were prepared by dissolving 100 parts of 98.5 mol% of a rubbery copolymer in 100 parts of toluene per sample. dimethylsiloxane units and 1.5 mol% of methyl vinylsiloxane units having a vinyldimethylsilyl group in molar chain 5 of the molecular chain, five parts of methylhydrogenpolypolysiloxane consisting of 95 mol% of methylanetoxysiloxane sane units with trimethylsilyl groups on both ends of the molecular chain and having a viscosity (20 cP) of about 40 silicon atoms in the molecule and about two parts of a reaction retarder of 3-methyl-1-butyn-3-ol and, in addition, chloroplatilic acid -anane complex of 200 ppm with respect to the total weight of the polysiloxane constituents in solution and finally 1, 5 and 15 parts of 1,1,3,3-tetramethyl isiloxane to samples No. 1, No. 2 and No. 3, respectively.

For comparison, Samples No. 4, No. 5, No. 6 and No. 7 were prepared according to essentially the same recipe as Example No. 1, however, omitting samples 1-7 1,1,3,3-20 of tetramethyldisiloxane and increasing the amount of methylhydrogenpolysiloxane in the fifth part 6. 10 and 15 in Samples No. 5, No. 6 and No. 7, respectively.

A sheet of polyethylene laminated paper was coated with each of the freshly prepared Samples 1-7 using 2 coating amounts of 0.8 g / m 2 (calculated as polysiloxane components) and the sheet was heat treated at 80 ° C for 15 seconds with a counter curing film and pSS coating film.

The same experiments performed above with the freshly prepared coating solutions were repeated using coating solutions stored at room temperature for two or four hours for the coating of the substrate sheet. The test results are shown in Table 1.

Example 2 35 Four baling solutions were prepared (samples

No. 8-11) with essentially the same recipe as above

92597 12, however, by replacing five parts of 1,1,3,3-tetramethyldisiloxane in each nMote in the same land, respectively, 1,3,5,7,9-pentamethylcyclopentanesiloxane, 1,1,1,3,7,9, 9,9-nonamethylpentazo-5-oxane, 1,1,1,3,5,7,9,11,13,13,13-undecamethylheptasiloxane and 1,1,1,3,5,7,9,11 , 13,15,17,19,19,19-tetra-dekametyylidekasiloksaania. The results of the hardness tests and crushing resistance tests are also shown in Table 1. Table 1 10

Nayte Cure Peeling Resistance, q No. ----

Newly Stored Counter- Stored Val- - Val- - 15 2 h 4 h 2 h 4 h t h 1 1 ABC 66 - 2 AAA 65 68 70 20 3 AAA 67 68 68 4 ACC 65 5 ABC 102 25 6 AAA 256 280 300 7 AAA 430 452 488 8 AAA 66 67 69 9 AAA 68 70 70 30_______ 10 AAA 230 250 280 11 AAA 250 273 300 13 92597

Example 3

A baling solution (Sample No. 12) was prepared by dissolving in 1,900 parts of toluene 50 parts of a rubbery copolymer consisting of 97.0 mol% of dimethylsiloxane units and 3.0 mol% of methyl vinylsiloxane units having a molecular chain in both are main groups of vinyldimethylsilyl groups, three parts of the same methylhydrogenpolysiloxane used in the previous examples, one part of 3,5-dimethyl-1-hex-10 syn-3-ol to retard the reaction and one part of 5-methoxybenzophenone to skin sensitone ppm calculated as platinum relative to the total amount of polysiloxane components in solution and finally five parts of methyldiethoxysilane were added.

For comparison, two more coating solutions (Samples 13 and 14) were prepared according to the same recipe as No. 12, but omitting methyl diethoxysilane from each sample and increasing the amount of methylhydrogenpolys-20-oxane in 14 of the three samples.

A sheet of polyethylene laminated paper was coated on each sample 12 to 14 using a coating amount of 2 0.8 g / m (calculated as polysiloxane ingredients) and each 25 sheets were heat treated at 80 ° C for 5 seconds and then UV-cured for 5 seconds. under a mercury lamp (80 W / cm) at different line speeds (30-50 m / min) to obtain UV curing of the organopolysiloxane composition. Thus, the hardenability of the release paper coating film was prepared, and the peel resistance was examined as in the previous examples; the results are shown in the following Table 2. The peel resistance was determined using test sheets prepared at a line speed of 30 m / min.

In addition to the experiments described above, which were performed with freshly prepared coating solutions, the same experiments were performed using coating solutions that had been stored at room temperature for four hours. These results are also shown in Table 2.

Table 2 5 ___—- NSyte Cure Peel Resistance, g No. --- 1-

Freshly prepared Stored Freshly stored 4 h made 4 h 10

Line speed, m / min 20 30 40 50 20 30 40 50 12 A A A A A A A 30 28 15 13 AAA C C C 32 14 AAA A A A 75 77 15 A A A A AAA 145 140 20 16 A A A ABC 138 17 AAA AAA 488 503

Example 4 A coating liquid (Sample No. 15) was prepared by mixing a uniform mixture of 100 parts of dimethylpolysiloxane having trivinylsilyl groups in the molecular chain end stations and having a viscosity of 1,000 cP. 5 parts of 3,5-dimethyl-1-hexyn-3-ol to slow down the reaction, one part of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photosensitizer, 3.0 parts of 1,3,5,7 -tetramethylcyclotetrazoxane and vinylsiloxane complex of chloroplatinic acid 200 ppm (calculated as platinum) relative to the total amount of polysiloxane constituents.

, 5 92597

For comparison, two more coating liquids (Samples 16 and 17) were prepared with the same composition as above, but omitting 1,3,5,7-tetramethylcyclotetrasiloxane from each of samples 16 and 5 17 and increasing the methyl polysilicon in sample 17 to 16. into nine parts.

A sheet of glossy paper was coated on each of the samples 15 to 17 using a coating amount of 1.0 g / ra (calculated as polysiloxane ingredients) and the sheet was subjected to 10 of the same heat treatment under the same example as in the previous example, but then under UV irradiation. -40 m / min for UV curing of the coating film. The hardening and peel-15 resistance of the coating film of the release paper thus prepared were examined in the same manner as in the previous examples; the test results are shown in Table 2. The shell resistance was determined using test sheets prepared at a line speed of 30 m / min. In addition to the experiments with fresh coating fluids described above, the same experiments were performed using coating fluids stored at room temperature for four hours. These results are shown in Table 2.

Claims (6)

92597 16 An organopolysiloxane composition for coating release paper, characterized in that it contains as a mixture: (A) 100 parts by weight of an organopolysiloxane having alkenyl groups attached to silicon atoms (B) 0.1 to 10 parts by weight of an organohydrogenpolysiloxane in which and at least 10 three hydrogen atoms directly attached to the silicon atoms of the molecule (C) a catalytic amount of a platinum compound, and (D) 0.1 to 10 parts by weight of an organosilane compound or an organopolysiloxane compound having at most six silicon atoms and at least one silicon atom in the molecule. The organopolysiloxane composition for use in the release paper coating according to claim 1, characterized in that it further contains up to 20 parts by weight of E (up to 10 parts by weight) per 100 parts by weight of the photosensitizer-combined component (A). Organopolysiloxane composition for use in the release paper coating according to claim 1, characterized in that the organosilane compound or organopolysiloxane compound used as component (D) is methyldimethoxysilane, methyldiethoxysilane, tri,3,3-triethane, triethoxysilane, 1,1,3-oxysilane, 1,3,5,5,5-heptamethyltrisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane or 1,1,1,3,5,7,9 , 9,9-nonamethylpentasiloxane. Organopolysiloxane composition for use in the release paper coating according to claim 2, characterized in that the amount of the component (E) 35 used as the photosensitizer is 2.0 to 6.0 parts by weight per 100 parts by weight of the component (A). . SvS organopolysiloxane composition for release paper backing according to claim 2, characterized in that the photosensitizer compound, component (E), is selected from acetophenone, propiophenone, benzophenone, xanthone, fluorenone, benzaldehyde, anthracene, anthracene, anthracene methylacetophenone, 4-chlorobenzophenone, 4-ethylbenzophenone, 5-methoxybenzophenone, 4-hydroxybenzophenone, benzoin-10-ethyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one and 2,2-diethoxyacetophenone. Organopolysiloxane composition for use in the release paper release baling according to claim 1, characterized in that the organopolysiloxane used as component (A) is a diorganopolysiloxane having a straight-chain molecular structure. $ «> (18,925> 7