JPH0532952A - Ultraviolet-crosslinkable hot-melt composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition having suppressed adverse effect on optical disk and excellent ultraviolet-curability by compounding a hot-melt base component and a saturated hydrocarbon resin oligomer with a specific amount of a specific reactive photo-polymerization initiator based on the sum of the main components. CONSTITUTION:The objective composition is produced by compounding (A) a composition obtained by compounding (i) 100 pts.wt. of a hot-melt base component having tacky adhesivity at ordinary temperature and (ii) 5-100 pts.wt. of a saturated hydrocarbon resin oligomer component containing one or more acryloyl groups in one molecule as an ultraviolet crosslinking component with (B) 0.05-2wt.% of a benzoyl compound of formula III containing (meth)acryloyl group and urethane bond group and produced by the addition reaction of a compound of formula I (R is H or CH3; n is 1-20) to a compound of formula II at an equivalent ratio (NCO/OH) of 1/(1-2), preferably 1/(1.5-2).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a UV-crosslinkable hot-melt composition, and more specifically, it shows excellent UV-curability by incorporating a small amount of a specific reactive photopolymerization initiator. The present invention relates to a hot melt composition intended to suppress adverse effects on an optical disk due to the use of a large amount of a conventional photopolymerization initiator in the agent use.

[0002]

BACKGROUND OF THE INVENTION As an adhesive in the field of optical disc manufacturing, a solventless type and fast-curing UV-crosslinkable hot-melt composition has been attracting attention. (Hereinafter referred to as HM base component), a UV-crosslinkable hot melt composition comprising a saturated hydrocarbon resin oligomer having at least one acryloyl group in one molecule as a UV-crosslinkable component, and a photopolymerization initiator is known. (JP-A-1
-141969). By the way, benzoin, benzoin alkyl ether-based, benzophenone-based, acetophenone-based, etc. are used as the photopolymerization initiator. Those which can be used by being compatible with or dispersed in the HM base component can be heated at around 110 to 120 ° C. In the molten state, a part of it disappears due to volatilization, resulting in a decrease in ultraviolet reactivity. Therefore, a large amount of photopolymerization initiator (usually 0.5 to 5% (% by weight, the same applies hereinafter) based on the total amount of the HM base component and the UV-crosslinkable component) must be blended. This will adversely affect the performance of the optical disc.

[0003]

Therefore, the present inventors have
As a result of extensive studies on a new photopolymerization initiator that can be blended in a small amount, a (meth) acryloyl group- and urethane bond group-containing benzoyl compound obtained by an addition reaction of a (meth) acryloyl group-containing isocyanate compound and a hydroxyl group-containing benzoyl compound Has been found to function as a reactive photopolymerization initiator, and exhibits excellent ultraviolet curability even when used in a small amount, and has completed the present invention.
The (meth) acryloyl group refers to an acryloyl group or a methacryloyl group.

That is, according to the present invention, as a reactive photopolymerization initiator, a compound represented by the formula:

[Chemical 2] (Wherein R and n have the same meanings as described above), a (meth) acryloyl group- and urethane bond group-containing benzoyl compound is blended in a proportion of 0.05 to 2%, which is an ultraviolet-crosslinkable hot melt. A composition is provided.

As the HM base component used in the present invention,
It has tackiness at room temperature and has the formula: AB, ABAA or BAAB [wherein A is a polystyrene block having a molecular weight of 2000 to 12500, and B is a molecular weight of 1000 to 250,000].
Or one or more of the block-like thermoplastic elastomers represented by the above polybutadiene block, polyisoprene block or ethylene butylene copolymer block], or synthetic rubber (polyisoprene, styrene rubber, butadiene rubber, butyl rubber, etc.) ), Polyolefin or polyolefin-based copolymer (polyethylene, polypropylene, ethylene-vinyl acetate copolymer, etc.), further tackifier (rosin resin, hydrogenated petroleum resin, hydrogenated terpene resin, phenol resin, coumarone resin, etc.), It is preferable to add an appropriate amount of a softening agent (process oil, paraffin oil, polybutene, polyisobutylene, etc.). The hydrogenated type tackifier has good compatibility, does not adversely affect the thermal stability, and has a low water absorption rate, and thus provides good corrosion resistance.

The ultraviolet-crosslinkable component used in the present invention 1
The saturated hydrocarbon-based resin oligomer containing at least one acryloyl group in the molecule is specifically a saturated hydrocarbon-based resin oligomer containing at least one hydroxyl group or carboxyl group in one molecule (hydrogenated polybutadiene). , Polybutene, hydrogenated polyisoprene, polyisobutylene, etc.) with an acrylate, urethane acrylate, epoxy acrylate or ester acrylate, and one or more of these are used. The amount used is usually 5 to 100 parts, preferably 10 to 100 parts of the HM base component (parts by weight, the same hereinafter).
It may be selected in the range of 40 parts. If it is less than 5 parts,
The effect of improving heat resistance by UV irradiation is low, and it is 100
If it exceeds the amount, the tackiness tends to decrease.

The above-mentioned (meth) acryloyl group- and urethane bond group-containing benzoyl compound [I] used as a reactive photopolymerization initiator in the present invention has the formula:

[Chemical 3] (Wherein R and n have the same meanings as described above), the (meth) acryloyl group-containing isocyanate compound [II] (isocyanate alkylene acrylate or isocyanate alkylene methacrylate) has the formula:

[Chemical 4] The hydroxyl group-containing benzoyl compound [III] of NCO
/ OH = 1/1 to 2, preferably 1 / 1.5 to 2 and produced by addition reaction. The addition reaction may be performed in a suitable solvent (for example, ethyl acetate, toluene, dimethylformamide, dimethylsulfoxide, tetrahydrofuran, etc.) at 40 to 120 ° C. for 30 minutes to 12 hours. Upon addition reaction, if necessary, a polymerization inhibitor (p-benzoquinone, hydroquinone, hydroquinone monomethyl ether, nitrosophenol, dinitrophenol, α-naphthoquinone, β-naphthoquinone, aminophenol, etc.) and a reaction catalyst (alkyltin such as dibutyltin laurylate). System compounds; amines such as triethylamine) may be added. The (meth) acryloyl group- and urethane bond group-containing benzoyl compound [I] obtained by such addition reaction is, for example, 1
Almost no volatilization disappears even after heating at 20 ° C. for 48 hours, and in addition to functioning as an original photopolymerization initiator, addition with a saturated hydrocarbon resin oligomer which is an ultraviolet-crosslinkable component through a double bond It will react and be incorporated into the polymer. The amount used is 0.05 to 2 with respect to the total amount of the HM base component and the UV-crosslinkable component.
%, Preferably 0.05 to 0.1%.
If it is less than 0.05%, the desired UV curability cannot be obtained,
Further, even if it exceeds 2%, there is no further improvement in the ultraviolet curing property, and it adversely affects the performance of the target product, especially the heat resistance, and causes corrosion of the recording film due to unreacted components. However, the object of the present invention cannot be achieved.

The ultraviolet (UV) crosslinkable hot melt composition according to the present invention is a benzoyl compound containing the above-mentioned HM base component, ultraviolet crosslinkable component and (meth) acryloyl group and urethane bond group as a reactive photopolymerization initiator. [I] is mixed in a predetermined ratio, and if necessary, a usual filler, an antiaging agent, a polymerization inhibitor and the like are added to the system.
It is melted at a temperature of 0 to 160 ° C. and used. The melt viscosity is generally 5000 to 500000 cps at 120 ° C.
Is set to.

The composition of the present invention is used for adhesives in the field of optical disc manufacturing, for example, and the bonding operation can be carried out by the following procedure. First, the composition of the present invention is melted, and is applied (for example, using a roll coater) to the adhesion surface of an adherend (for example, an optical disk substrate) with a thickness of 10 to 50 μm, and then UV is irradiated to overlap the adherend. A total of 0.2 to 20 kg / cm < ² > is pressed, or UV is irradiated after overlapping and pressing.

[0010]

EFFECT OF THE INVENTION According to the composition of the present invention having the above constitution, the reactive photopolymerization initiator compounded at 110 to 120 ° C.
Since there is no volatilization due to heating in the vicinity, it is possible to add a small amount of reactive photopolymerization initiator, and with this,
It is possible to suppress the adverse effect on the optical disk, which is a conventional problem.

[0011]

EXAMPLES The present invention will now be described with reference to Examples and Comparative Examples.
This will be specifically described. Examples 1-3Production of reactive photopolymerization initiator  formula:

[Chemical 5] 31 parts of a methacryloyl group-containing isocyanate compound of the formula:

[Chemical 6] 44.8 parts of a hydroxyl group-containing benzoyl compound (N
CO / OH = 1/2) in 100 parts of dehydrated ethyl acetate,
The reaction is carried out at 60 to 85 ° C. for 150 minutes in the presence of the reaction catalyst. The presence of active isocyanate groups was not observed in the reaction product.

[0012]UV crosslinkable hot melt composition  Ingredients: polystyrene-ethylene butylene copolymer block-like thermoplastic elastomer [Califlex GX-1726 manufactured by Shell Chemical Co., Ltd.] --72 parts Styrene-ethylene / butylene-styrene copolymer block-like thermoplastic elastomer [ Shell Chemical Co., Ltd., Califlex GX-1652] --- 192 parts Hydrogenated terpene resin tackifier [Yasuhara Yushi Co., Ltd., Clearon M115] --450 parts Polybutene softener [Idemitsu Kosan Co., Ltd.] Polybutene 300H] --- 120 parts Terminal acryloyl group-containing hydrogenated polybutadiene oligomer [Nippon Soda Co., Ltd., TEAI-3000] -218 parts The above-mentioned reactive photopolymerization was initiated with respect to 1052 parts of the total amount of the above components.
The reaction product obtained in the production of the agent is converted into solid content and the following Table 1 is shown.
UV-crosslinking type
A hot melt composition is obtained.

Comparative Examples 1 to 2 In Example 1, no reactive photopolymerization initiator was added or 2,2-dimethoxy-2-phenylacetophenone (m, p
A UV crosslinkable hot melt composition is obtained in the same manner except that (64 to 67 ° C.) is used instead (see Table 1).

[0014]Temperature rising creep test  Immediately after melting each composition at 120 ° C (initial), or
After leaving it in the molten state at 120 ° C for 48 hours,
After) Thickness on two acrylic plates (25 x 60 x 1.5 mm)
It is applied at 50μ and UV is applied at 1000mj / cm.²Irradiation
After that, wrap it by 20 mm and immediately stack it at 80 ° C for 10
kg / cm²Press to tighten. The obtained laminated plate is 0.4 ° C
Creep test (load 1
00g) and evaluated by vertical drop temperature. The results are shown in Table 1.
Write together.

[Table 1]

From the results shown in Table 1, in Examples 1 to 3 in which the novel reactive photopolymerization initiator of the present invention was used, the creep resistance was lowered even when the hot-melt state continued for a long time during use. However, in Comparative Example 2 in which the conventional photopolymerization initiator was used, it can be seen that the creep temperature after melting and leaving is significantly lowered.

Claims (1)

Claims: 1. Reactive photopolymerization with respect to the total amount of a saturated hydrocarbon resin oligomer containing at least one acryloyl group in one molecule as a hot melt base component and an ultraviolet crosslinking component. Formula as an initiator: (In the formula, R is H or CH ₃ , and n is 1 to 20)
The ultraviolet-crosslinkable hot melt composition is characterized by blending the (meth) acryloyl group- and urethane bond group-containing benzoyl compound represented by the above at a ratio of 0.05 to 2% by weight.