JPH0726146A - Radiation curable organopolysiloxane composition - Google Patents

Abstract

PURPOSE:To obtain a composition capable of ready radiation core, excellent in adhesion to a base and easy to release by blending plural organopolysiloxanes represented by specified structural formulae respectively. CONSTITUTION:The composition is composed mainly of (A) an organopolysiloxane of formula I [R<1> is H, a 1 to 4C alkyl or phenyl; R<2> is the same group as R<1> or a group of formula II (R<3> is H or methyl; n is 1 to 3) and the group of formula II occupies 0.3 to 3.0mol% based on the whole organic groups bonded to silicon atoms in one molecule; (c) is 0 to 3; (a)+(b)X(c)+(d)=500 to 1000] and (B) an organipolysiloxane of formula III [R2 is R1 or a group of formula II. The group of formula II occupies 5 to 20mol% based on the whole organic groups; (g) is 0 to 3; (e)+(f)X(g)+(h)=50 to 200]. The mixture ratio of the component (A) to the component (B) is 10/90 to 40/60 on weight base.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a radiation-curable organopolysiloxane composition, and in particular, it is easily cured by irradiation with radiation and adheres well to a substrate such as a plastic film. The present invention relates to a radiation-curable organopolysiloxane composition that can be easily peeled off.

[0002]

2. Description of the Related Art Radiation-curable organopolysiloxane compositions are known to consist of organopolysiloxanes containing a (meth) acryloxy group in the molecule. As a method for producing this composition, epoxy group ring-opening addition is used. A method of introducing a (meth) acryloxy group into siloxane by using a reaction (see JP-A-63-135426 and JP-A-2-45533), and a method of introducing a (meth) acryloxy group into siloxane by using a hydrosilylation reaction. Method (JP-A-48)
-48000, refer to Japanese Patent Laid-Open No. 2-163166).

However, this type of radiation-curable organopolysiloxane composition is mainly used as a coating agent for surface treatment, because the cured film has a property of easily peeling off a sticky substance. In addition, it is used as a backing agent for adhesive tapes and a coating agent for release paper for adhesive labels.

[0004]

On the other hand, in recent years, mechanical sticking has been performed on adhesive tapes and adhesive labels, and since mechanical sticking is performed at high speed, the force required for peeling increases. For this reason, a large force is applied to the release paper, and the release paper is apt to vibrate, and sound is generated by this vibration (peeling sound). Since this peeling noise is noise, it adversely affects the working environment. In addition, the fact that this peeling sound is generated means that the fluctuation range of peeling force becomes large, and the mechanical sticking device is designed so that tapes and labels can be stuck at a fixed position with a certain peeling force. On the other hand, when the peeling width of the peeling force increases, there is a problem that the machine does not function normally, and this peeling noise does not occur often when the peeling force is small, but it occurs when the peeling force increases to some extent, There is a demand for a release agent that does not generate a release noise even when the release force is large.

[0005]

The present invention relates to a radiation-curable organopolysiloxane composition which solves the above disadvantages and problems, and the radiation-curable organopolysiloxane composition has the general formula (I).

[Chemical 4] [Wherein R ¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, and R ² is the same group as R ¹ or the general formula (I
I)

[Chemical 5] (Wherein R ³ is a hydrogen atom or a methyl group, and n is 1 to 3), and 0.5 to 3.0 mol% thereof is generally contained with respect to all organic groups bonded to a silicon atom in one molecule. It is a group represented by the formula (II), c is 0 to 3, and a + b × c + d = 500.
~ 1,000] organopolysiloxane (A)
And the general formula (III)

[Chemical 6] (R ¹ is the same as the above, R ² is the same group as R ¹ or the general formula (II)
In the group represented by, 5 to 20 mol% is a group represented by the general formula (II) with respect to all organic groups bonded to a silicon atom in one molecule, g is 0 to 3, e + f × g + h = 50-200)
With organopolysiloxane (B) as a main component,
The mixing ratio (weight ratio) of organopolysiloxane (A) / organopolysiloxane (B) = 10/90 to 40 /
It is characterized by being 60.

That is, the present inventors have conducted various studies to develop an organopolysiloxane composition which is easily cured by irradiation with radiation such as ultraviolet rays and electron beams, and does not generate peeling noise even when the peeling force is large. Compounding an acrylic-containing silicone base with a silicone having a high degree of polymerization and a low acrylic content in a specific ratio, specifically, the organopolysiloxane (A) represented by the general formula (I) and the general formula (III) When the organopolysiloxane (B) is mixed in a specific range, the organopolysiloxane is easily cured by irradiation with radiation, and when the organopolysiloxane is applied to a plastic film and cured by irradiation, the cured film is formed. It has been found that it exhibits excellent peeling properties with respect to adhesive substances, and that it does not generate peeling noise even when the peeling force is large. Check the Ukoto has led to the completion of the present invention. This will be described in more detail below.

[0007]

The present invention relates to a radiation-curable organopolysiloxane composition, which comprises the organopolysiloxane (A) represented by the general formula (I) and the general formula (III). Organopolysiloxane (B) shown is replaced with organopolysiloxane (A) / organopolysiloxane (B) = 10 / 90-40
It is characterized by being mixed in a weight ratio of / 60. A film obtained by applying the organopolysiloxane composition to a substrate such as a plastic film is easily cured by irradiation with radiation. It exhibits excellent releasability with respect to an adhesive substance, which has the advantage that it does not generate a peeling noise even when the peeling force is large.

The radiation-curable organopolysiloxane composition of the present invention comprises a mixture of the organopolysiloxane (A) represented by the general formula (I) and the organopolysiloxane (B) represented by the general formula (III). To be done. This organopolysiloxane (A) has the general formula (I)

[Chemical 7] Wherein R ¹ is a hydrogen atom or an atom or group selected from a lower alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group, or a phenyl group. It is preferably a methyl group from the standpoint of easiness of release and easy peeling of the sticky substance.

Further, R ² is the same atom or group as R ¹ ,
Or general formula (II)

[Chemical 8] R ³ is a hydrogen atom or a methyl group, and n is 1 to 3.
However, if the amount of the group represented by the general formula (II) is less than 0.5 mol% of the organic group bonded to the silicon atom in one molecule, the curability by radiation is significantly reduced,
If this amount exceeds 3.0 mol%, peeling noise will be generated, so it is necessary to set this in the range of 0.5 to 3.0 mol%. Furthermore, the average number of silicon atoms in one molecule [a + c
When (b + 2) + d + 2] is less than 500, peeling noise is generated, and when it is 1,000 or more, the viscosity becomes too high and it becomes difficult to apply this composition to a substrate or the like.
This needs to be 500 to 1,000, but if the value of c is 4 or more, the viscosity increases during the synthesis and the synthesis becomes difficult, so this should be 0 to 3, preferably 1 to 2. Is good.

The organopolysiloxane (B) used here has the general formula (III)

[Chemical 9] And R ¹ and R ² are the same atoms or groups as those in the above-mentioned general formula (I), but among the organic groups bonded to the silicon atom in one molecule, the general formula (II If the amount of the group represented by (4) is less than 5 mol%, the curability by radiation is significantly reduced, and if it is more than 20 mol%, the curability by radiation is improved, but the peeling force of the cured film is significantly increased. This is 5 because peeling becomes difficult.
It is necessary to set it in the range of 20 mol%, and the average number of silicon atoms present in one molecule [e + g (f + 2) + h
+2] is less than 50, the curability due to radiation is reduced, and when it is more than 200, the viscosity of the composition becomes high, making it difficult to apply it to a substrate, etc. It must be in the range of 200, but this g
The value of is preferably 0 to 1.

The organopolysiloxane composition of the present invention is a mixture of the organopolysiloxane (A) and the organopolysiloxane (B). The organopolysiloxane (A) and the organopolysiloxane (B) are mixed.
The mixing ratio (weight ratio) of the organopolysiloxane (A) / organopolysiloxane (B) is 10 /
If it is less than 90, the effect of reducing the peeling sound will not be obtained even with heavy peeling during high-speed peeling, and if it is more than 40/60, the curability due to radiation will decrease, so this is 10 / 90-40
A range of / 60 is required, but preferably 20
The range of / 80 to 30/70 is preferable.

The above-mentioned organopolysiloxane (A),
The synthesis of the organopolysiloxane represented by the general formulas (I) and (III) constituting (B) is performed by

[Chemical 10] (Here, R ³ is a hydrogen atom or a methyl group, R ⁴ is the same as R ¹ or a group represented by the general formula (II), and L is 0 to 3)
An organopolysiloxane represented by

[Chemical 11] (R ³ is the same as above, m is 3 to 7), and (c) a general formula

[Chemical 12] (R ³ is the same as above, R ⁵ is a group represented by the general formula (II), P is a cyclic siloxane represented by 3 to 7), and (I), (B), (C) Of 0.1 to 2.0 parts by weight of CH ₃ SO ₃ H or CF ₃ SO ₃ H as a catalyst for 100 parts by weight of the total amount of the acid equilibration reaction at a reaction temperature of 80 to 100 ° C. and a reaction time of 4 to 10 hours. You can do this.

The radiation-curable organopolysiloxane of the present invention can be obtained by mixing the above-mentioned organopolysiloxane (A) and organopolysiloxane (B) within a predetermined range as described above. Is a photoinitiator such as acetophenone, benzophenone, 4-chlorobenzophenone, 4,4-dimethoxybenzophenone, 4-methylacetophenone, benzoin methyl ether, benzoin trialkylsilyl ether, diethylamine ethanol, piperidine, etc. An oxygen curing inhibition inhibitor, a reactive diluent, an organic solvent, a leveling agent, a filler, an antistatic agent, a defoaming agent, a pigment, an organopolysiloxane having no radical reactive group, and the like may be added.

The radiation-curable organopolysiloxane of the present invention thus obtained can be used as a back-treating agent for pressure-sensitive adhesives, a protective coating agent for metals and plastics, and a base for paints. 0.01 ~ 200μ by using bar coater, gravure coater, reverse coater or spraying on paper, various plastic films, metal foil such as aluminum
After coating so as to have a film thickness of about m, it may be irradiated with radiation and cured.

The radiation includes electron rays, α rays, β rays,
Gamma rays or mercury arc, ultraviolet rays generated from medium pressure mercury lamps, high pressure mercury lamps, etc. are exemplified, but the dose for curing the above-mentioned coating film is 2 to 5 Mrad if it is an electron beam.
The photopolymerization initiator is added to the organopolysiloxane composition in the case of ultraviolet rays, and when a high pressure mercury lamp of 2 kW (80 w / cm) is used, for example, the distance from 8 cm is 0.1.
Irradiate for ~ 10 seconds.

The radiation-curable organopolysiloxane composition of the present invention has a thickness of 0.01 to 2.0 μm on the surface of a plastic film such as polypropylene film, polyester film, polyethylene film represented by OPP film. When the coating film is applied as described above and the coating film is cured by irradiating it with the above-mentioned radiation, the cured coating film exhibits excellent peeling property. The advantage is that no peeling noise is generated even when the value is large.

[0017]

EXAMPLES Next, synthesis examples, examples and comparative examples of the organopolysiloxane constituting the organopolysiloxane composition of the present invention are shown. In the examples, parts are parts by weight, viscosity and refractive index at 25 ° C. And the physical property values in the examples are those measured by the following test methods. (Curable) 1 g / of the organopolysiloxane composition of the present invention
After applying m ² to the OPP film, the oxygen concentration is 50ppm.
The amount of electron beam irradiation (Mr) until a completely cured film is obtained when cured by electron beam irradiation in a nitrogen stream as shown below.
Ad), the judgment of this hardening was made when the coated surface did not fall off even if the coated surface was rubbed with a finger, and it did not become cloudy.

(Peeling Force and Peeling Sound) The organopolysiloxane composition of the present invention was cured by irradiating it with an electron beam at the lowest dose for measuring the curability, and after forming this cured film on the OPP film, Stick a hot-melt tape on the surface of the cured film, age at 70 ° C for 24 hours,
Thereafter, the OPP film coated with siloxane was pulled at a peeling speed of 8 m / min at an angle of 180 ° using a tensile tester, and the force (g / 5 cm) required for peeling was measured. Further, the peeling sound was determined by whether or not there was a peeling sound when the peeling force was measured in a quiet constant temperature chamber. This peeling sound was (maximum peeling force-minimum peeling force) / average peeling force = δ, The value of δ will be represented.

(Residual Adhesion Rate) A cured film of an organopolysiloxane composition was formed on an OPP film as in the case of peeling force measurement, and a polyester tape / Lumilar 31B (trade name of Nitto Denko Corporation) was formed on the surface. ] Was adhered, a load of 20 g / cm ² was applied, heat treatment was performed at 70 ° C. for 24 hours, and then the tape was peeled off and adhered to a stainless steel plate. Then, the tape was peeled from the stainless steel plate at an angle of 180 ° at a peeling speed of 300 mm / min, and the force required for peeling (g / 2.5
cm) and the force required to peel the untreated standard tape from the stainless steel plate (g / 2.5 cm), and the force required to peel this untreated standard tape (g / 2.5 cm). 2.5c
Expressed as a percentage (%) with respect to m).

(Synthesis Example) A 1-liter four-necked flask equipped with a stirrer, a thermometer, and a Dimroth was charged with the formula.

[Chemical 13] 31 parts of (a) organopolysiloxane represented by

[Chemical 14] 592 parts of (b) cyclic dimethyl polysiloxane represented by
And expression

[Chemical 15] (C) 310 parts of (c) cyclic polysiloxane and 20 ppm of the total amount of this siloxane

[Chemical 16] Was added with the compound shown by and stirred at room temperature for 5 minutes, and then CH ₃ SO ₃ H as a catalyst was added to the total amount of siloxane.
1.0 wt% was added, and the acid equilibrium reaction was performed at a temperature of 90 to 100 ° C for 6 to 10 hours. After the reaction was completed, NaHCO ₃ was added in an amount 3 times that of CH ₃ SO ₃ H, and the mixture was heated at 110 ° C for 2 to 3 After performing a neutralization reaction for a period of time and then filtering and stripping, each siloxane unit having an average composition formula of organopolysiloxane was M =

[Chemical 17] D = 18

[Chemical 18] D ^A = formula 19

[Chemical 19] When abbreviated as T = CH ₃ SiO _3/2 , siloxane (1) represented by M ₃ D ₈₀ D ^A ₁₈ T could be obtained with a yield of 90%.

[0021] This is a pale yellow transparent liquid having a viscosity of 210 cp, a refractive index of 1.427 and an acryloxy group content of IR,
It was confirmed by ¹ H-NMR that the content was 8.7 mol%, which was confirmed in (a), (b) and (c) above.
The following organopolysiloxanes (2) to (7) were synthesized in the same manner except that the ratio of the components was changed. The composition, degree of polymerization, acryl group content, viscosity, and refractive index are shown in Table 1. It was as shown.

[0022]

[Table 1]

Examples 1 to 5 30 parts of siloxane (3) was added to 70 parts of the siloxane (1) obtained in the above synthesis example and mixed well to prepare the radiation-curable organopolysiloxane composition of the present invention. Along with (Example 1), siloxanes (4) to (7) were added to the siloxane (1) obtained in the above Synthesis Example in the amounts shown in Table 2 and mixed, and the radiation curable organopolysiloxane composition of the present invention was added. (Examples 2 to 5) were prepared and their curability, peeling force, residual adhesion ratio and peeling noise were measured, and the results shown in Table 2 below were obtained.

Comparative Examples 1 and 2 The siloxane (1) obtained in the above-mentioned synthesis example was used alone (Comparative Example 1), and 70 parts of this siloxane (1) and 30 parts of this siloxane (2) were mixed well. Using the organosiloxane composition, the curability, peel force,
The residual adhesion ratio and the peeling noise were measured, and
The result as shown in was obtained.

[0025]

[Table 2]

Example 6, Comparative Examples 3 to 4 10 parts of siloxane (5) was added to 90 parts of the siloxane (1) obtained in the above-mentioned synthesis example and mixed well, and the radiation-curable organopolypolyamide of the present invention was added. Create a siloxane composition,
When the curability, peeling force, residual adhesion ratio and peeling noise of this product were measured, the results shown in Table 3 were obtained. However, for comparison, the compounding amount of the siloxane (1) and the siloxane (5) was 5 parts of the siloxane (5) to 95 parts of the siloxane (1) (Comparative Example 3), and the siloxane (1). ) 50 parts of siloxane (5) to 50 parts
When the same measurement was performed on the parts (Comparative Example 4), the results shown in Table 3 were obtained.

[0027]

[Table 3]

EXAMPLE 7 A radiation curable organopolysiloxane composition of the present invention comprising 70 parts of siloxane (1) and 30 parts of siloxane (3) prepared in Example 1 was formulated.

[Chemical 20] The photoinitiator Darocur 1173 [made by Merck] shown in Figure 3 was added to a plastic film with a thickness of 38 μm made of OPP and a thickness of 1.2 μm using an offset printing machine. So that it becomes N
₂ Under aeration, a high pressure mercury lamp (80w / cm) was used to irradiate ultraviolet rays from a distance of 8 cm for 0.5 seconds to cure this, and a peeling film was obtained. The physical properties of this film were examined. As a result, the peeling force was 35 g / 5 cm, and no peeling noise was generated.

[0029]

INDUSTRIAL APPLICABILITY The present invention relates to a radiation curable organopolysiloxane composition, which is represented by the general formula (I) and the general formula (III) as described above. The organopolysiloxane (B) is mixed with the organopolysiloxane (A) / organopolysiloxane (B) in a weight ratio of 10/90 to 40/60. The composition is easily cured by irradiation with radiation and adheres well to a substrate such as plastic, and the cured film obtained by curing this can easily release the adhesive substance, and has a peeling force during high-speed peeling. It has an advantage of showing the effect that the peeling noise does not occur even when the volume becomes large.

Claims (1)

[Claims] 1. A compound represented by the general formula (I): [Wherein R ¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, and R ² is the same group as R ¹ or the general formula (I
I) [Chemical 2] (Wherein R ³ is a hydrogen atom or a methyl group, and n is 1 to 3), and 0.5 to 3.0 mol% thereof is generally contained with respect to all organic groups bonded to a silicon atom in one molecule. It is a group represented by the formula (II), c is 0 to 3, and a + b × c + d = 500.
~ 1,000] organopolysiloxane (A)
And the general formula (III): (R ¹ is the same as the above, R ² is the same group as R ¹ or the general formula (II)
In the group represented by, 5 to 20 mol% is a group represented by the general formula (II) with respect to all organic groups bonded to a silicon atom in one molecule, g is 0 to 3, e + f × g + h = 50-200)
With organopolysiloxane (B) as a main component,
The mixing ratio (weight ratio) of organopolysiloxane (A) / organopolysiloxane (B) = 10/90 to 40 /
A radiation-curable organopolysiloxane composition, which is 60.