JPS5821671B2 - Polychloroprene resin - Google Patents

Description

[Detailed description of the invention] The present invention relates to novel adhesive compositions.

More specifically, polychloroprene is derived from a cyclopentadiene monomer, a vinyl ethyl and/or (meth)acrylic acid ester, an α,β unsaturated dicarboxylic acid and/or the α,β unsaturated dicarboxylic acid anhydride. This invention relates to an adhesive composition with improved adhesive strength and open time obtained by blending a cyclopentadiene resin.

In general, polychloroprene adhesives have good adhesion properties, and have excellent weather resistance, aging resistance, alkali resistance, and acid resistance, and are widely used industrially to bond a wide variety of objects. There is.

Even when polychloroprene rubber is used alone as an adhesive, it has excellent adhesive strength at room temperature due to its crystallinity, but at high temperatures the adhesive strength decreases due to the melting of the crystals, so general polychloroprene adhesives do not have this drawback. For improvement purposes, alkylphenol resins have been used alone or in combination with metal oxides such as magnesium oxide, as solutions in volatile organic solvents, or in the form of emulsions.

Improvements in the high-temperature adhesive strength (sometimes referred to as heat resistance) of polychloroprene adhesives have been achieved mainly by improving the alkylphenol resin and its derivatives, and by blending metal oxides and other auxiliary materials.

However, this alkylphenol resin is expensive, and it is desirable to construct a heat-resistant polychloroprene adhesive composition using relatively inexpensive raw materials.

The present inventors first used a thermopolymerized resin of a cyclopentadiene monomer and an unsaturated monomer having a polar group, thereby achieving adhesive strength at room temperature equal to or higher than that using a phenolic resin. It was found that it has the following effect.

(Japanese Patent Application No. 49-31281) However, the POIJ chloroprene adhesive using the above-mentioned thermopolymerized resin has some difficulty in heat resistance, and there are restrictions in applications requiring heat resistance.

On the other hand, in JP-A-49-2128035, an unsaturated polybasic acid or its anhydride is reacted with a hydrocarbon resin obtained by polymerizing a cracked oil fraction obtained by thermal cracking and catalytic cracking of petroleum. It is stated that by using the resulting resin, an adhesive with excellent heat resistance can be obtained.

However, when a general hydrocarbon resin modified by such a method is used, the adhesion retention time, which is generally called open time, is shortened. Sufficient adhesion force cannot be obtained unless adhesive is applied inside the adhesive.

Therefore, a short open time is inconvenient and undesirable in actual construction.

Therefore, the inventors of the present invention conducted extensive studies on various hydrocarbon resins, and found that ordinary hydrocarbon resins were not satisfactory for the purpose of improving the above-mentioned adhesive strength, especially heat resistance and open time. The present invention was completed based on the recognition that the above object can be achieved only in a cyclopentadiene resin having a specific composition and properties.

That is, the present invention combines 100 parts by weight of polychloroprene, cyclopentadiene monomer holes, and vinyl ester and/or (meth)acrylic acid ester (B) into (A)/(B).
) in a weight ratio of 85/15 to 55/45, and a thermal polymer obtained by heating a mixture containing α, β unsaturated dicarboxylic acid and/or the acid anhydride (Q), or A softening point of 100 to 160°C obtained by thermally polymerizing the compounds (5), (B) and (C) in specific proportions.
and cyclopentadiene resin 10 with an acid value of 10 to 100
-100 parts by weight polychloroprene adhesive compositions with improved adhesion and open time.

The present invention is characterized by blending the above-mentioned specific cyclopentadiene resin into polychloroprene, and optionally containing metal oxides, anti-aging agents, pigments, fillers, etc. for the purpose of improving adhesive strength. Known additives for polychloroprene adhesives and, if necessary, resins known for compounding polychloroprene adhesives such as alkylphenol resins, terpenephenol resins, or polyterpene resins, are dissolved in a volatile organic solvent. , or an adhesive composition in the form of an emulsion.

Cyclopentadiene monomer A used in the production of cyclopentadiene resin includes cyclopentadiene,
Lower Diels-Alder adducts such as methylcyclopentadiene and dimers, dimers and codimers of these monomers and mixtures thereof are used.

Industrially, dicyclopentadiene is used, which can be easily converted to cyclopentadiene by thermal decomposition during the reaction.

Furthermore, among the monomers B, lower fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, and vinyl caproate are used as the vinyl ester, and as the (meth)acrylic ester, acrylic acid or Esters of methacrylic acid and lower alcohols having 1 to 5 carbon atoms can be used.

The monomers selected from the vinyl esters and (meth)acrylic esters of monomer (B) may be used alone or in combination of two or more.

Among these, vinyl acetate and methyl methacrylate are particularly preferred industrially.

In addition, α, β unsaturated dicarboxylic acids or their anhydrides (Q can be maleic acid, fumaric acid, citraconic acid, itaconic acid, etc. or their acid anhydrides, etc.) used in the production of the cyclopentadiene resin. , these can be used alone or in combination of two or more.

Industrially particularly preferred are maleic acid and maleic anhydride.

In the thermal polymerization of the cyclopentadiene resin of the present invention, in addition to the monomers (5), (B), and (Q), as other copolymerizable monomers of up to 20% by weight of the total monomers, butadiene is added. , isoprene, diolefins such as pentagene,
Even if a C4 to C7 fraction containing aromatic vinyl such as styrene, alpha methyl styrene, or a thermally polymerizable unsaturated compound generated during thermal decomposition of petroleum etc. is used, the effects of the present invention will not be impaired. .

Thermal polymerization of cyclopentadiene monomer (5) and vinyl ester and/or (meth)acrylic acid ester (B), or cyclopentadiene monomer hole, vinyl ester and/or (meth)acrylic acid Ester (B) and α
Thermal polymerization of β-unsaturated dicarboxylic acids or their anhydrides (q) belongs to known techniques, and a mixture of these monomers is reacted with benzene,
in the presence or absence of a hydrocarbon solvent such as toluene or xylene at 250 to 300°C, preferably 260 to 2
at 80°C for 0.5 to 20 hours, preferably 1 to 10 hours,
After polymerization by heating in the absence of a catalyst, unreacted products are removed by conventional polymer purification means such as distillation.

It can be produced by removing low polymers and solvents.

Further, as the polymerization method, any of a batch method, a semi-batch method, and a continuous method can be employed.

Generally, the higher the monomer concentration during the polymerization reaction and the longer the reaction time, the higher the softening point of the resin can be obtained.

In addition, when a thermal polymerization product of cyclopentadiene monomer (A) and vinyl ester and/or (meth)acrylic ester (Q) is reacted with α,β unsaturated dicarboxylic acid or its anhydride (Q), Generally, it is preferable to heat the resin to 150° C. or higher in the presence or absence of a radical initiator, and heating to 300° C. or higher is not preferable because coloring becomes noticeable and the softening point of the resin increases.

Thermal polymerization of the monomers (A) and (B), or (A)
, (B) and (q), (A)/(
The preparation weight ratio of B) is 85/15 to 55/45. Preferably, it is necessary that it is 80/20 to 60/40,
If the weight ratio of (A)/(B) is larger than this range, the improvement in open time and heat resistance will not be sufficient when used as a polychloroprene adhesive; on the other hand, if it is smaller than this range, The softening point of the resulting resin is low, and the adhesive strength of the adhesive is not sufficiently improved.

The softening point of the obtained cyclopentadiene resin is 1
00 to 160°C, preferably 120 to 150°C,
Below 100℃, the adhesive does not have sufficient heat resistance;
If the temperature exceeds 60°C, the solubility in volatile organic solvents will decrease, and the open time, adhesive strength and flexibility of the adhesive will decrease, which is not preferable.

The range of acid value of cyclopentadiene resin is 10
~100. Preferably it is 20-70.

If the acid value is less than 10, the heat resistance of the adhesive will not be sufficient, and if the acid value exceeds 100, the film on the adhesive surface will become brittle, resulting in a lack of flexibility, reduced adhesive strength, and poor adhesion. This is limited because the water resistance of objects also deteriorates.

The polychloroprene constituting the adhesive composition of the present invention is a polymer of chloroprene and is commercially available under various names, but it is preferable to select a variety with relatively high crystallinity.

Metal oxides used as desired components include magnesium oxide, zinc oxide, calcium oxide, and the like.

Volatile organic solvents commonly used when used as contact adhesives include aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as n-hexane, octane, etc., ethyl acetate, acetic acid, etc. Organic solvents that normally dissolve polychloroprene, such as ester solvents such as butyl, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, are used alone or in combination to increase solubility and control the volatilization rate. For this purpose, mixtures of several of these organic solvents are usually used.

In the composition of the present invention, the proportion of each component used is usually 10 to 100 parts by weight, preferably 20 to 60 parts by weight of the cyclopentadiene resin, which is the tackifier of the present invention, per 100 parts by weight of polychloroprene. 0 to 20 parts by weight of metal oxide and 0 to 5 parts by weight of anti-aging agent, if desired.

Furthermore, fillers, pigments, water and other auxiliary agents may be added in desired amounts.

The method of blending these rubbers, tackifying agents and other desired additives is a method commonly used by those skilled in the art. roll additives,
A method in which the adhesive resin and the metal oxide are mixed in advance in the solvent and then mixed in a solution containing polychloroprene as the main component. There is a method of blending.

Furthermore, when a polychloroprene emulsion is used as a base, 1) the cyclopentadiene resin of the present invention is dispersed in water using a common emulsifier, and both are mixed together with other desired additives to form an emulsion. You can also do it.

The present invention will be explained below with reference to examples, but it is not limited to these examples.

Reference Example 1 Production of cyclopentadiene resin The cyclopentadiene resin used in the present invention was produced under the following conditions using an autoclave with a capacity of 1 mm, unless otherwise specified.

480. ! 9r
Copolymerized monomer (〃)
120gr Reaction temperature 260°C Reaction time 3 hours Resin obtained by removing the solvent and unreacted materials by distillation from the reaction mixture obtained by reacting under the conditions as above or commercially available petroleum resin 100.9r and maleic anhydride. (variable) to 5
The mixture was charged into a 00yd flask and heated for 5 hours at 200°C.

Example 1 After kneading 100.9r of polychloroprene (trade name: Neoprene AD, manufactured by Showa Neoprene), 49r of magnesium oxide, 5.9r of zinc oxide, and 50g of cyclopentadiene resin in a roll, toluene/n-hexane/acetic acid was added. Ethyl 1/1/I CM.

An adhesive formulation was obtained by dissolving the adhesive in a mixed solvent of 371Fr.

Apply the adhesive three times to two sheets of No. 10 canvas after leaving it for one hour. After the last application, leave it at 25℃ for 10 minutes to evaporate the volatile solvent. Press the cotton canvas with a roll, leave it for 7 days at 25°C, then peel it off at speed 5.
The peeling adhesive strength was measured at 0 m1/m.

Note that the measurement temperature was carried out at two points: 25°C and 60°C.

Furthermore, the open time, which indicates the usable life of the adhesive, was expressed as the time required for a test piece coated with the adhesive to lose its tackiness when touched at 25°C.

The first results were evaluated using cyclopentadiene resins obtained by reacting maleic anhydride with thermally polymerized resins obtained by varying the amount of vinyl acetate as hinyl ester monomers and varying the acid value. It is a table.

For comparison, commercially available petroleum resins (C5 series, C9 series) without post-maleation or post-maleation,
Table 2 also lists the results of evaluating commercially available phenolic resins.

As is clear from Table 1, the invention examples (Experiments 1 to 6) are different from the control examples (experiments 1 to 6) using cyclopentadiene resins other than the invention.
Experiments 7 to 15) and a control example using commercially available petroleum resins, their maleated products, and phenolic resins (Experiment 16)
-20), both the adhesion strength at open time and at 25°C were significantly improved, and the adhesion strength at high temperatures was also improved compared to the control example (Experiments A7-19). Excellent for noticeable use.

Example 2 Same as Reference Example 1 except that methyl methacrylate was used instead of vinyl acetate in the synthesis of cyclopentadiene resin.
The same procedure as in Example 1 was carried out, and an adhesive was prepared and evaluated in the same manner as in Example 1.

The results are listed in Table 2.

As shown in Table 2, the effects of the present invention can be sufficiently achieved even when a cyclopentadiene resin obtained using methyl methacrylate is used in place of vinyl acetate.

Reference Example 2 Instead of the method for producing cyclopentadiene resin described in Reference Example 1, a total of 480 fir of monomers with the following formulation and 120.9 r of xylene were charged into an autoclave with a capacity of 11, and the mixture was heated at 260°C under a nitrogen atmosphere. After reacting for 3 hours, unreacted substances and solvent were removed by distillation to obtain cyclopentadiene resins as shown in Table 3.

Example 3 Using the cyclopentadiene resins A and B obtained in Reference Example 2, an adhesive was prepared and evaluated in exactly the same manner as in Example 1. The results are shown in Table 4.

As shown in Table 4, the effects of the present invention are obvious even if the manufacturing method is changed.

On the other hand, adhesives using cyclopentadiene resins obtained by methods other than the present invention have insufficient open time, adhesive strength, and heat resistance.

Claims (1)

[Claims] 1. 100 parts by weight of polychloroprene, cyclohen. Tadiene monomer (A) and vinyl ester and/or (
α, β unsaturated dicarboxylic acid and/or its Softening point 100-160°C and acid value 1 obtained by reacting acid anhydride (Q or thermally polymerizing a mixture of compound (4), @ and (0) in the above weight ratio
Cyclopentadiene resin having 0 to 100 10 to 1
00 parts by weight of an adhesive composition.