JP3047655B2 - How to bond silicone rubber to plastic parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to silicone rubber such as two-component condensation-cured silicone and two-part foamable organopolysiloxane for plastic parts generally used for automobile parts, electric appliances, electronic parts, various containers and the like. In particular, the silicone rubber is favorably applied to parts made of (super) engineering plastic having no adhesiveness to silicone rubber, such as polyethylene, polypropylene, nylon, and polyphenylene sulfide. The present invention relates to a bonding method for bonding.

[0002]

2. Description of the Related Art Two-component condensation-cured silicones are used for molding and the like, and are generally known to have no adhesiveness at all. The two-part foamable organopolysiloxane also adheres to metals, glass, etc., but polyethylene, polypropylene, ABS, PET,
Does not adhere to plastics such as PBT.

Generally, in order to improve the adhesiveness of silicone rubber, a primer treatment of an adherend, an adhesive agent such as an amine-functional silane and a partial hydrolyzate thereof, and an amine-functional siloxane are added to a curable liquid silicone rubber. When a platinum-based compound is used as a catalyst for addition and curing of the epoxy resin, an epoxy group, (meth)
Addition of a silane compound having an acrylic group, a vinyl group, or the like, a siloxane compound, isocyanuric acid, or the like, plasma treatment of an adherend, corona discharge treatment, and the like are performed.

[0004]

Among these, primer treatment involves environmental pollution due to the organic solvent contained in the components, and drying after the primer is applied to the adherend and the organic solvent is completely evaporated. There is a disadvantage that the process requires about 20 minutes or more. Furthermore, the organic solvent may cause defects such as cracks in the plastic to be adhered.

In addition, when an adhesion-imparting agent such as an amine-functional silane is added, it can be adhered to various adherends at room temperature, but does not adhere to PPS, PE, PP, etc., and a platinum compound catalyst is used. When added to the curable liquid silicone rubber contained therein, there is a fatal disadvantage that the catalyst poison prevents the composition from being cured.

Further, when a silane, siloxane compound, isocyanuric acid or the like having an epoxy group, a (meth) acrylic group, a vinyl group, etc. is added, it does not poison the catalyst, but 1-2 hours at 120 ° C. to 150 ° C. It is necessary to heat for about an hour, and therefore, it is not suitable for low heat-resistant plastics such as polypropylene (PP).

[0007] In addition, the plasma treatment has the disadvantage that continuous productivity is poor and the equipment is very expensive because of the batch processing, and the corona treatment can only treat film-like adherends. Has disadvantages.

Accordingly, an object of the present invention is to provide a plastic part which is extremely difficult to adhere to a plastic part and a silicone rubber at room temperature, very easily and firmly, and which solves the above-mentioned disadvantages of the prior art. An object of the present invention is to provide a method for bonding a silicone rubber to a component.

[0009]

According to the present invention, a portion to be bonded of a plastic part is irradiated with ultraviolet rays having short wavelengths of 184.9 nm and 253.7 nm in advance. After that, a curable liquid silicone rubber is applied to the irradiated portion and cured.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in detail. As described above, the present invention first irradiates a portion of a plastic component to be bonded with ultraviolet light containing a short wavelength in advance.

The above-mentioned plastic parts are made of (super) engineering plastic having no adhesion to silicone rubber, such as polyethylene, polypropylene, nylon, phenol, polyphenylene sulfide, etc. , Electronic components, various containers, and the like.

The ultraviolet light having the above short wavelength has a wavelength of 1 wavelength.
Ultraviolet light including both short wavelengths of 84.9 nm and 253.7 nm, and is generally ultraviolet light generated from a low-pressure mercury lamp or the like. The output of the light source is not particularly limited, but is preferably 10 W to 1,000 W industrially.

If the distance from the light source to the object to be irradiated is too far, the effect is reduced, and if the distance is too close, the light source may be damaged. Therefore, the distance from the light source is 0.2 cm to 50 cm, more preferably 0.5 to 30 cm. Range. If the irradiation time of the ultraviolet ray is too short, the adhesiveness cannot be obtained, and if it is too long, the plastic matrix is eroded. Therefore, the irradiation time is 1 second to 60 minutes, more preferably 5 seconds to 30 minutes.

In the present invention, after the above-mentioned irradiation with ultraviolet rays, a curable liquid silicone rubber is applied to the irradiated portions and cured.

The curable liquid silicone rubber described above is a two-component condensation-cured silicone or a two-part foamable organopolysiloxane.

The two-component condensation-cured silicone has the following components (A), (B) and (C): (A) both ends of the molecular chain are blocked with hydroxyl groups, and the viscosity at a temperature of 25 ° C. is from 100 to 1, Diorganopolysiloxane of 000,000 centistokes (B) Two molecules of hydrolyzable group directly bonded to silicon atom in one molecule
And (C) a curing catalyst, wherein the component (A) is a main component, and the components (B) and (C) are a curing agent.

The aforementioned organopolysiloxane of the component (A) has the general formula

Embedded image (However, R ₄ and R ₅ are monovalent same or different substituted or unsubstituted hydrocarbon groups, and n is a value such that the viscosity of the organopolysiloxane becomes 100 to 1,000,000 centistokes at 25 ° C.) Wherein R ₄ and R ₅ are an alkyl group such as a methyl group, an ethyl group, or a propyl group;
Vinyl groups, alkenyl groups such as allyl groups, phenyl groups, tolyl groups, aryl groups such as naphthyl groups, and those in which some of the hydrogen atoms of these hydrocarbon groups are substituted with halogen atoms, nitrile groups, etc. However, R ₄ and R ₅ are preferably methyl groups from the viewpoints of ease of synthesis and viscosity of the composition.

If the viscosity of the organopolysiloxane is less than 100 centistokes, the silicone rubber after curing will not have sufficient elongation, and if it exceeds 1,000,000 centistokes, the handling operation will be difficult, which is not preferable.
Thus, the range is preferably from 100 to 1,000,000 centistokes, and more preferably from 500 to 20,000 centistokes.

The above-mentioned organosilicon compound of the component (B) is a compound which undergoes a condensation reaction with a silanol group of the organopolysiloxane of the component (A) to crosslink the component (A).
Either a silane compound or a siloxane compound may be used as long as it has a hydrolysis group directly bonded to a silicon atom in one molecule.

The hydrolyzable group directly bonded to the silicon atom in the component (B) includes, for example, an alkoxy group such as a methoxy group, an ethoxy group and a propoxy group, an acyloxy group such as an acetoxy group and an octanoyloxy group, and a dimethylketoxime group. A ketoxime group such as an ethylmethylketoxime group, an alkenyloxy group such as an isopropenyloxy group, a 1-ethyl-2-methylvinyloxy group, an amino group such as a dimethylamino group and a diethylamino group, a dimethylaminooxy group, and a diethylaminoxy group. And an amide group such as an aminooxy group such as a group, an N-methylacetamido group, and an N-ethylacetamido group.

Specific examples thereof include compounds having the following structural formulas. In these formulas, X represents a hydrolyzable group.

Embedded image

The organic compound having a hydrolyzable group directly bonded to a silicon atom of the component (B) is used in an amount of 0.1 to 50 parts by weight, preferably 1 to 20 parts by weight, per 100 parts by weight of the component (A). is there.
If the amount of the component (B) is too small, sufficient mechanical strength cannot be obtained. If the amount is too large, there is an adverse effect such as an economic disadvantage or a poor deep-section curability.

The above-mentioned component (C) functions as a catalyst for accelerating the condensation reaction between component (A) and component (B). Specifically, lead-2-ethyl octate, dibutyltin dioctane Tate, dibutyltin diacetate,
Dibutyltin dilaurate, butyltin-2-ethylhexoate, iron-2-ethylhexoate, manganese-
2-ethylhexoate, zinc-2-ethylhexoate, stannous caprylate, tin naphthenate, tin oleate, tin butylate, titanium naphthenate, zinc naphthenate, cobalt naphthenate, zinc stearate, etc. Metal salts of organic carboxylic acids, tetrabutyl titanate, tetra-
Organic titanates such as 2-ethylhexyl titanate, triethanolamine titanate and tetra (isopropenyloxy) titanate; organic titanium compounds such as organosiloxytitanium and β-carbonyltitanium; alkoxyaluminum compounds; 3-aminopropyltriethoxysilane; Aminoalkyl group-substituted alkoxysilanes such as N- (trimethoxysilylpropyl) ethylenediamine, amine compounds such as hexylamine, dodecylamine phosphate and salts thereof, quaternary ammonium salts such as benzyltriethylammonium acetate, potassium acetate, sodium acetate Lower fatty acid salts of alkali metals such as, lithium oxalate, dimethylhydroxylamine, diethylhydroxylamine, guanidine compounds and guanidyl group-containing silanes A siloxane or the like, and used in combination of one kind by itself or more species.

The amount of the component (C) used is any suitable amount, but preferably 0.01 parts by weight based on 100 parts by weight of the component (A).
To 5 parts by weight, more preferably 0.1 to 3 parts by weight. If this is too small, it will take a very long time to cure, and if it is too large, the curing time will be extremely short and the workability will be worse, and furthermore, the heat resistance of the cured product will be inferior to the weather resistance Become.

In addition, the above-mentioned components (A) to
In the three-component system (C), various fillers may be further added in optional amounts, for example, 5 to 2,000 parts by weight per 100 parts by weight of the component (A). As these fillers, for example, fine powder silica, silica aerogel, precipitated silica, diatomaceous earth, iron oxide, zinc oxide, metal oxides such as titanium oxide, and those obtained by subjecting their surfaces to silane treatment, calcium carbonate, magnesium carbonate, carbonate Metal carbonates such as zinc, asbestos, glass wool, carbon black, fine mica, fused silica powder, polystyrene, polyvinyl chloride,
Polypropylene and the like.

In the above three-component system, thixotropy-imparting agents such as polyethylene glycol and derivatives thereof, pigments, dyes, antioxidants, antioxidants, fungicides,
Antistatic agents, antimony oxides, hardening agents such as paraffin chloride, thermal conductivity improvers such as boron nitride and aluminum oxide, and carbon functional silanes having amino groups, thiol groups, epoxy groups, etc., carboxylic acids A known adhesion promoter such as a metal salt or a metal alcoholate may be used.

The two-part foamable organopolysiloxane is a foamable liquid silicone rubber, and specifically, [I]
And the composition shown in [II] .

[I] Those containing the following components (a), (b), (c) and (d). (B) Organopolysiloxane containing at least two alkenyl groups in one molecule (b) Organopolysiloxane containing silanol group in one molecule (c) Organopolysiloxane having hydroxysilyl group in one molecule (d) Curing catalyst

The above components (a) to (d) are components (a),
A two-part foamable organopolysiloxane comprising (b) and (c) as main components and component (d) or components (a) and (d) as curing agents.

As described above, the organopolysiloxane of the component (a) has an alkenyl group bonded to at least two silicon atoms in one molecule. this is,
The following general formula

Embedded image Indicated by Here, R ₁ is an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group and the like, an aryl group such as a phenyl group and a tolyl group, or a carbon atom of these groups. Same or different unsubstituted or substituted groups except aliphatic unsaturated groups selected from chloromethyl group, trifluoropropyl group, cyanoethyl group, etc. in which part or all of the bonded hydrogen atoms are substituted by halogen atoms, cyano groups, etc. A monovalent hydrocarbon group, R ₂ is an alkenyl group such as a vinyl group or an allyl group, m is 50 to 100,000 and n / m = 0 to
It is 0.1, but it is supposed that the compound contains at least two alkenyl groups represented by R ₂ in one molecule.

As described above, component (b) is an organopolysiloxane having a silanol group bonded to at least one silicon atom in one molecule, and reacts with component (c) to generate hydrogen gas. In the case of an organopolysiloxane having a silanol group bonded to three or more silicon atoms, the organopolysiloxane acts as a crosslinking agent simultaneously with the blowing agent. This is desirably of a lower molecular weight than component (a) in order to make it compatible with component (a).

These may be in the form of a chain.

Embedded image And the like are exemplified.

In the above general formula, R ₃ is a methyl group,
1 carbon atoms such as ethyl group, propyl group, butyl group, etc.
Or an aryl group such as an alkyl group, a phenyl group or a tolyl group, or a chloromethyl group in which part or all of the hydrogen atoms bonded to the carbon atoms of these groups have been substituted with a halogen atom, a cyano group, or the like; The same or different unsubstituted or substituted monovalent hydrocarbon groups excluding aliphatic unsaturated groups selected from propyl group, cyanoethyl group and the like;
It is 1,000 and m and n are from 1 to 50, and it is said that this contains at least one hydroxy group in one molecule.

The component (c) is an organohydrogensiloxane or an organohydrogenpolysiloxane, which undergoes a condensation reaction with the component (b) to generate hydrogen gas and act as a foaming agent. It acts as a crosslinking agent by an addition reaction.

This may be a mono-, di-, or trihydroxysilane, or a linear or cyclic hydrogen polysiloxane, but has a higher molecular weight than component (a) in order to be compatible with the composition. It is desirable to be low.

The amount of the component (c) is such that the amount of the SiH bond is less than 1 mol of the sum of the alkenyl group contained in the component (a) and the silanol group contained in the component (b). In such an amount, the addition reaction with the component (a) and the condensation reaction with the component (b) become insufficient, so that a sufficient expansion ratio cannot be obtained. The product obtained in (1) becomes brittle, a large excess of SiH bond remains, and there is a possibility of causing a change with time, so that a predetermined foaming property cannot be obtained. Therefore, the alkenyl group contained in the component (a) and the component (b)
With respect to the sum of the silanol groups contained therein, this SiH
It is necessary to add in a range where the amount of the bond becomes 1 to 50 times mol, but it is necessary to add it in a range where it becomes 3 to 10 times mol.

Further, the curing catalyst of the component (d) is used as a catalyst in an addition reaction between the component (a) and the component (c) and a condensation reaction between the component (b) and the component (c). . This may be a known platinum or a platinum compound or a platinum complex. Therefore, this may be platinum black or platinum supported on silica, carbon black, or the like, or chloroplatinic acid, an alcohol solution of chloroplatinic acid, platinum chloride. Platinum compounds, such as a complex of acid and olefin or vinyl siloxane, are exemplified.

The above-mentioned components (a) to (d) are used as the main ingredients by uniformly mixing predetermined amounts of the components (a), (b) and (c), and the components (a) and (d) or By uniformly mixing a predetermined amount of the component (d), a two-part room temperature curable composition can be obtained as a curing agent. By foaming reaction and cross-linking reaction of this composition by mixing a main component and a curing agent at a predetermined ratio, the composition is cured into a foamable rubber elastic body.

The composition comprising the above (a) to (d) further contains fillers such as zinc oxide, magnesium oxide and calcium carbonate, fumed silica, precipitated silica, titanium dioxide, aluminum oxide, and quartz powder. , Talc and bentonite, etc., fibrous fillers such as asbestos, glass fiber and organic fiber, coloring agents such as pigments and dyes, heat resistance improvers such as red iron oxide and cerium oxide, cold resistance improvers, polyethers etc. Thixotropic agent, rust inhibitor, γ
- acryloxy propyl trimethoxy silane adhesion improving agent such as a liquid reinforcing agent reticulated polysiloxane consisting triorganosiloxane units and SiO ₂ units, may be added viscosity modifier such as non-functional silicone oils, these May be added in a predetermined amount as needed.

[II] Those containing the following components (a) to (e). (A) General formula

Embedded image Α-ω-dihydroxyorganopolysiloxane represented by the formula (wherein, R ₁ and R ₂ are different or the same substituted or unsubstituted monovalent hydrocarbon groups except aliphatic unsaturated hydrocarbon groups, and x is 2,000 to (Indicates an integer of 3,000)

(B) General formula

Embedded image Wherein R ₃ , R ₄ and R ₅ are different or the same unsubstituted or substituted monovalent hydrocarbon groups except aliphatic unsaturated hydrocarbon groups, and m is 2 to 20, n represents an integer of 3 to 20)

(C) General formula

Embedded image A polyorganohydrogensiloxane having at least two units in one molecule represented by the following formula:
And per mole of the total amount of silanol groups in (b),
An organohydrogenpolysiloxane in which the amount of SiH groups is in the range of 0.5 to 30 mol (wherein R ₆ is a monovalent hydrocarbon group excluding aliphatic unsaturated hydrocarbon groups, and a is 0, 1, 2
From above, b is a number selected from 1, 2, and 3, respectively.
a + b is any number of 1, 2 or 3)

(D) Platinum or platinum compound

(E) General formula

Embedded image Or the general formula

Embedded image An organic silicon compound represented by the formula (wherein, R ₇ , R ₈ ,
R ₉ , R ₁₀ and R ₁₁ each represent a hydrogen atom or a carbon atom
10 identical or different unsubstituted or substituted aliphatic monovalent hydrocarbon groups)

The composition is a room-temperature-curable foamed polysiloxane composition having particularly excellent foaming ratio and foam regulating properties,
Two-component foaming agent composed of four components (a), (b), (d) and (e) as main components and two components (a) and (c) as curing agents among the above components It is an organopolysiloxane.

Α, ω used as the above-mentioned component (a)
The dihydroxyorganopolysiloxane has a degree of polymerization of x to provide mechanical strength to the cured polysiloxane foam;
Must be in the range of 200 to 3,000,
A range from 300 to 2,000 is preferred. When x is less than 2,000, the elongation of the polysiloxane foam after curing is not sufficient, and when x exceeds 3,000, handling becomes difficult, which is not preferable.

R ₁ and R ₂ are different or the same monovalent substituted or unsubstituted monovalent hydrocarbon groups excluding aliphatic unsaturated hydrocarbon groups. Examples of such groups include a methyl group and an ethyl group. , Propyl, butyl, ventil,
Alkyl groups such as hexyl group, phenyl group, tolyl group, an aryl group such as a naphthyl group, a chloromethyl group, is exemplified monovalent hydrocarbon groups substituted, such as 3,3,3-trifluoropropyl group, R ₁ And R ₂ may be the same or different. In particular, it is preferable that both R ₁ and R ₂ are methyl groups from the viewpoint of availability and viscosity of the composition.

The above-mentioned component (b) is a component that improves the expansion ratio of the expandable polysiloxane composition by its hydroxy group and imparts good thixotropic properties to the composition to give good foam-regulating properties. , The above general formula

Embedded image Is an organopolyhydroxypolysiloxane represented by the formula: R, R ₃ , R ₄ and R ₅ are different or the same type of substituted or unsubstituted monovalent hydrocarbon groups except aliphatic unsaturated hydrocarbon groups, and from the viewpoint of availability and viscosity of the composition. , R, R ₃ , R ₄ and R ₅ are preferably all methyl groups.

M is an integer of 2 to 20, and n is an integer of 3 to 20, and it is particularly preferable that m and / or n be in the range of 10 to 20. If n is less than 3, the expansion ratio will be low, and a room-temperature-curable expanded polysiloxane composition having an excellent expansion ratio will not be obtained.

The ratio of m / n is preferably 1 or more. When the ratio of m / n is less than 1, (SiR ₅ (O
H) O) _n part silanol group becomes relatively unstable,
In some cases, it may be difficult to obtain a stable foaming ratio and foam controllability.

The amount of component (b) added is 1 to 50 parts by weight, preferably 1 to 20 parts by weight, per 100 parts by weight of component (a). If the addition amount of the component (b) is less than 1 part by weight, the expansion ratio becomes low, and a room temperature-curable expanded polysiloxane composition having an excellent expansion ratio cannot be obtained. On the other hand, if it exceeds 50 parts by weight, the mechanical strength of the polysiloxane foam becomes insufficient.

The above-mentioned component (c) is a component having a hydrogen atom directly bonded to a silicon atom, and is composed of an organic silicon compound having a hydroxyl group directly bonded to the silicon atom in component (a) or (b). Is a component that generates hydrogen gas by a dehydrogenation reaction and performs cross-linking.

This component (c) has the general formula

Embedded image Is a polyorganohydrogensiloxane having at least two units in one molecule. In the formula, a is a number selected from 0, 1 or 2, b is a number selected from 1, 2 or 3, and a + b indicates a number selected from 1, 2 or 3. R ₆ is 1 excluding an aliphatic unsaturated hydrocarbon group
It is a monovalent hydrocarbon group, and specific examples thereof include an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a benzyl group, and a hexyl group. From the viewpoint of availability, it is particularly desirable that R ₆ is a methyl group.

The hydrogen atom directly connected to the silicon atom may be located at the terminal of the molecule or in the side chain.
It may be any of a chain, a ring, and a branch.

The amount of component (c) used is such that the total amount of silanol groups in components (a) and (b) is
The amount is in the range of 0.5 to 30 mol, preferably in the range of 2 to 20 mol. If the amount is less than 0.5 mol, a room-temperature-curable foamed polysiloxane composition having excellent expansion ratio and foam regulating property cannot be provided. If it exceeds 30 mol, the mechanical strength of the polysiloxane foam becomes insufficient.

The component (d) is the component (a) or (b)
And a platinum or platinum-based compound that promotes the dehydrogenation reaction between component and component (c), such as platinum metal, chloroplatinic acid, a complex of platinum and an olefin-based compound, platinum and a silane containing a vinyl group, Examples thereof include a complex with siloxane and a phosphite complex of platinum. Among these, chloroplatinic acid and a complex of platinum and an olefin-based compound are preferred from the viewpoint of providing the composition before curing and providing an appropriate foaming rate.

The amount of component (d) used is in the range of 0.1 to 200 ppm, preferably 1 to 50 ppm, as platinum metal, based on the total weight of components (a), (b) and (c). If it is less than 0.1 ppm, the dehydrogenation reaction will be slow,
Even if it exceeds 0 ppm, no particularly good result is obtained,
Economically disadvantageous.

The above component (e) is generally an addition type RTV
Of the general formula

Embedded image Or

Embedded image Indicated by

In the formula, R ₇ , R ₈ , R ₉ , R ₁₀ and R ₁₁ are each independently a hydrogen atom, a methyl group, an ethyl group,
An aliphatic monovalent hydrocarbon group having 1 to 10 carbon atoms such as an alkyl group such as a propyl group and a butyl group, an aryl group such as a phenyl group and a tolyl group, and an alkenyl group such as a vinyl group and an allyl group. This acetylene alcohol derivative contributes to the reaction control of the foam and the improvement of the foam regulating property based on the SiH / SiOH dehydrogenation reaction of the present invention,
The greatest feature of the composition [II] is that the present component is used in combination.

The following can be exemplified as specific examples of the component (e).

Embedded image

The organic silicon compound is added in an amount of 0.001 to 10 parts by weight, preferably 0.001 to 1 part by weight, based on 100 parts by weight of the total of the components (a), (b), (c) and (d). .
The range is 0 parts by weight. If the amount is less than 0.001 part by weight, the viscosity of the composition will greatly increase in a short time, so that the workability will be reduced, and if it exceeds 10 parts by weight, the curability of the composition will be significantly reduced.

In the above-mentioned composition [II], a vinyl group-containing low molecular siloxane may be further used as a control agent, but this is slightly inferior to the acetylene alcohol derivative in foam control.

The above-mentioned foamable polysiloxane composition may further contain, as necessary, a diorganic polyorganosilyl siloxane or vinyl compound having both ends or one end blocked with a triorganosilyl group, as long as the effect is not impaired. A group-containing silane, siloxane, or the like can be added to either the main agent or the curing agent, and additives such as a filler, a pigment, a dye, a heat resistance improver, and a flame retardant can also be used in combination.

[0064]

According to the present invention, as described above, a portion of a plastic part to be bonded is irradiated with ultraviolet rays containing both 184.9 nm and 253.7 nm in advance. The irradiation of ultraviolet rays is an important step for bonding silicone rubber to plastic parts in the present invention. 184.9nm and 253.7nm wavelength
Ultraviolet rays containing both are generally emitted from low-pressure mercury lamps and have the following effects.

Ozone generation by absorption of oxygen of 184.9 nm ultraviolet ray Ozone decomposition and generation of active oxygen (O) by absorption of ozone of 253.7 nm ultraviolet ray Decomposition of chemical bond on plastic surface by 253.7 nm and 184.9 nm Oxygen on active plastic surface, active oxygen (O)
Oxidation by

In the present invention, an active group such as a hydroxyl group, a carboxyl group, or a carbonyl group is formed on the surface of an inert plastic such as polypropylene, polyethylene, or polyphenylene sulfide by the action of the above-described ultraviolet irradiation.

In the case of a two-component condensation-cured silicone as the curable liquid silicone rubber, a silanol group (≡Si—OH) and a hydrolyzable group such as an alkoxysilyl group (≡Si—OR ₁ , R ₁ is an aliphatic alkyl group), a ketoximesilyl group (≡Si—O—N ＝ C)
R ₂ R ₃ , R ₂ , and R ₃ are the same or different aliphatic alkyl groups), aminoxysilyl group (−Si—O—NR
There are groups such as ₂ R ₃ ), and these groups and the above-mentioned hydroxyl group, galboxyl group, carbonyl group and the like generated by irradiating the plastic surface with ultraviolet rays cause a chemical bond to develop adhesiveness. (Cohesive failure)

In the case of a two-part foamable organopolysiloxane as the curable liquid silicone rubber, a silanol group (Si—OH), a hydrosilyl group (Si—H) and the like are present in this component. The group and the above-mentioned hydroxyl group, carboxyl group, carbonyl group and the like generated by ultraviolet irradiation on the surface of the plastic form a chemical bond, whereby adhesiveness (cohesion failure) is developed.

[0069]

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Example 1 The following solutions A and B were mixed at a ratio (weight) of 100: 5, and short-wave ultraviolet rays were irradiated with the following ultraviolet irradiation apparatus at a distance of 5 cm from the light source for an irradiation time of 5 minutes. Test pieces pretreated by irradiation under conditions (polyethylene, polypropylene, polyphenylene sulfide, nylon, iron, copper,
On the glass) and the adhesion state after 2 hours was confirmed.
Table 1 shows the results.

(1) Ultraviolet Irradiation Apparatus An “ultraviolet cleaning and reforming apparatus PL8-200” manufactured by Sen Engineering Co., Ltd. was used.

(2) Preparation of two-component condensation-cured silicone (a) Preparation of liquid A 100 parts by weight of α-ω dihydroxydimethylpolysiloxane having a viscosity of 1,000 cst at 25 ° C. 100 parts by weight of calcium carbonate having an average particle size of 1.5 μm Part The above two components were designated as solution A. (B) Preparation of solution B ◎ 100 parts by weight of siloxane represented by the following formula

Embedded image ◎ Aminopropyltriethoxysilane 10 parts by weight ◎ Dibutyltin dioctate 5 parts by weight The above three components were used as liquid B.

Comparative Example 1 The same experiment as in Example 1 was performed except that no ultraviolet ray was irradiated. Table 1 shows the results.

Comparative Example 2 The same experiment as in Example 1 was performed, except that a primer was applied instead of irradiating with ultraviolet rays and left for 5 minutes. Table 1 shows the results.

[0075]

[Table 1]

As is clear from Table 1, in Comparative Example 1 in which no ultraviolet light was irradiated and in Comparative Example 2 in which a primer was applied instead of ultraviolet light irradiation, nylon, iron, copper,
Although it has adhesiveness to glass, it did not adhere to polyethylene, polypropylene, or polyphenylene sulfide at all. On the other hand, in Example 1 according to the present invention, good adhesion was exhibited to any adherend.

Example 2 Each of nylon 6-6, polypropylene, hard polyvinyl chloride, ABS and polyphenylene oxide was irradiated with short-wavelength ultraviolet rays under irradiation conditions of a distance of 2 cm from the light source and an irradiation time of 60 seconds. A pretreatment was performed, and the following main agent and curing agent were mixed at a ratio of 1: 1 and applied. The organosiloxane foamed and cured in 10 minutes, and the adhesion after 1 hour was examined.
Table 2 shows the results.

(1) Ultraviolet Irradiation Apparatus As in the first embodiment, an "ultraviolet cleaning and reforming apparatus PL8-200" manufactured by Sen Engineering was used.

(2) Preparation of Two-Part Foamable Organopolysiloxane (A) Preparation of Main Agent

Embedded image Α-ω-dihydroxyorganopolysiloxane having a viscosity at 25 ° C. of 20,000 cs, expressed by the formula: 90 parts by weight ◎

Embedded image 5 parts by weight of an organopolyhydroxypolysiloxane having a viscosity at 2% of 150 cs represented by the following formula: 1.0 parts by weight of an isopropanol solution containing chloroplatinic acid 25

Embedded image The silicon compound having an acetylenically unsaturated group represented by the formula: 0.05 parts by weight ◎ Dimethyl polysiloxane oil 20 parts by weight ◎ Fumed silica 10 parts by weight The above components were used as the “base agent”.

(B) Preparation of curing agent

Embedded image 90 parts by weight ◎ Chemical formula

Embedded image 20 parts by weight of polyorganohydrogensiloxane represented by ◎ 20 parts by weight of dimethylpolysiloxane oil ◎ 10 parts by weight of fumed silica The above components were referred to as “curing agent”.

Example 3 The ultraviolet irradiation time for polypropylene was 0 second, 30 seconds,
An experiment was conducted in the same manner as in Example 2 except that the time was changed to 60 seconds, and the adhesion state was examined. Table 3 shows the results.

Comparative Example 3 An experiment was conducted in the same manner as in Example 2 except that the pretreatment by irradiation with ultraviolet rays was not carried out, and the state of adhesion was examined. Table 2 shows the results.

[0083]

[Table 2]

[0084]

[Table 3]

As is apparent from Table 2, in the case of the two-part foamable organopolysiloxane, in Comparative Example 3 in which the pretreatment by irradiation with ultraviolet rays was not performed, nylon 6, 6, polypropylene, hard polyvinyl chloride, ABS and polystyrene were used. It did not exhibit adhesion to all of the phenylene oxides. On the other hand, in Example 2 according to the present invention in which the pretreatment was performed by irradiation with ultraviolet light, good adhesion was exhibited to any adherend.

Further, as is clear from Table 3, the irradiation time of the ultraviolet light to the adherend shows no adhesiveness at zero seconds, shows partial adhesiveness at 30 seconds, and complete adhesiveness at 60 seconds. Gender.

[0087]

As described above, according to the present invention, a plastic component is irradiated with short-wavelength ultraviolet rays and pre-treated, so that it can be used at room temperature in a short time and without using an organic solvent like a primer. Silicone rubber can be adhered to plastic parts to the level of cohesive failure. In addition, since no primer is used, there is no on-site or environmental pollution caused by an organic solvent or the like.

Continuation of the front page (72) Inventor Norihiro Katsuno 1456, Hazashi-cho, Hachioji-shi, Tokyo Three Bond Co., Ltd. (56) References JP-A-6-5150 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 5/12 C08J 7/00 C08J 7/04 WPI (DIALOG)

Claims (3)

(57) [Claims] 1. A method of manufacturing a plastic part excluding silicone, which is to be adhered to, at least in advance, at 184.9 nm and 253.
Irradiation with ultraviolet light containing a short wavelength of 7 nm, and then
A method of applying a silicone rubber to a plus part, which comprises applying and curing a curable liquid silicone rubber selected from the following (1) to (3) at the irradiation location. (1) (A) Both ends of the molecular chain are blocked with hydroxyl groups, and
At a temperature of 100 ° C.
Diorganopolysiloxane (B) which is a Stints
Organosilicon compound having two or more (C) curing catalyst including above (A), (B) and (C)
Curable liquid silicone rubber (2) (a) having at least two alkenyl groups per molecule
Organopolysiloxanes containing silanol groups in the molecule (b)
Rokisan (c) Oruganopo with hydroxy silyl groups in a molecule
Lisiloxane (d) curing catalyst containing the above (a) to (d), and
The components (a), (b) and (c) as main ingredients, and
(D) or the above components (a) and (d) as curing agents
Two-part foamable organopolysiloxane (3) (a) having the general formula : Α-ω-dihydroxyorganopolysiloxane represented by the formula
(Wherein R ₁ and R ₂ are each independently an aliphatic unsaturated hydrocarbon group)
Ku heterologous or homologous substituted or unsubstituted monovalent charcoal hydrocarbon
Group, x is an integer of 200 to 3,000) (b) the general formula ## STR2 ## An organopolyhydroxypolysiloxane represented by the formula (formula
Wherein R ₃ , R ₄ and R ₅ are each an aliphatic unsaturated hydrocarbon group.
Heterologous or similar unsubstituted or substituted monovalent hydrocarbons
Group, m is 2 to 20, n is an integer of 3 to 20) (c) general formula 3] Having at least two units in one molecule represented by
An organohydrogensiloxane, (a) and
And per mole of the total amount of silanol groups in the component (b),
An amount of the organosilicon group such that the SiH group is in the range of 0.5 to 30 mol;
Hydrogen polyene polysiloxane (wherein R ₆ is an aliphatic
A monovalent hydrocarbon group excluding a saturated hydrocarbon group, a is 0,
B is a number selected from 1, 2, and 3, respectively, from 1, 2
And a + b is any number of 1, 2, or 3.
That) (d) platinum The platinum-based compounds (e) general formula 4] Or the general formula : (In the formula, R ₇ , R ₈ ,
R ₉ , R ₁₀ and R ₁₁ are each a hydrogen atom or a carbon number
1-10 identical or different unsubstituted or substituted aliphatic 1
(A) to (e),
And the components (a), (b), (d) and (e)
A main component, and the components (a) and (c) as a curing agent.
Two-part foamable organopolysiloxane 2. The plastic part is polyethylene,
2. The plus part according to claim 1, which is made of polypropylene, nylon or polyphenylene sulfide.
How to bond rubber . 3. The curable liquid silicone rubber represented by the above (1) is a two-component condensation-cured silicone containing the component (A) as a main component and the components (B) and (C) as a curing agent. Item 1 plus silicone
A method of bonding rubber .