JPH0129806B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a copolymer comprising an ethylenically unsaturated compound, and more particularly to a method for producing a copolymer of a bicycloorthoester compound having a vinylbenzyl group and an ethylenically unsaturated compound. Generally, it is well known that monomers such as ethylenically unsaturated compounds undergo considerable volume shrinkage during homopolymerization and copolymerization; for example, the volume shrinkage rates during polymerization of ethylene, acrylonitrile, methyl methacrylate, and styrene are 66.0%, 31.0%,
21.2% and 14.5%. If the volume shrinkage during polymerization is large, for example, when used as a molding material, dimensional accuracy may be lost, when used as a casting material, the cast product may be distorted due to shrinkage, or the adhesive strength with the mold may be reduced. There are problems such as gaps being created. In addition, when used as a paint, internal distortion may cause a decrease in adhesion to the coated plate and cause warping, and when used as an adhesive, internal distortion may cause a decrease in adhesive strength, warpage, deformation, etc. cause problems. Furthermore, it is also known that common crosslinkable polymers shrink when crosslinked and cured. Epoxy resins have a low shrinkage rate during crosslinking and curing due to ring opening of epoxy groups, so they are widely used in paints, adhesives, molded products that require dimensional accuracy, cast products, etc.
The shrinkage rate of epoxy resin varies somewhat depending on the type of crosslinking agent, curing time and temperature, but is about 1 to several percent (see Kobunshi, Vol. 27, February issue, 1978, pp. 108-111). Substances that do not substantially shrink or preferably expand upon polymerization of monomers or crosslinking of polymers are currently highly sought after as materials for the construction of sophisticated devices, such as strain-free composites, adhesives, and casting materials. It is valued and explored. As a result of extensive research into new comonomers for ethylenically unsaturated compounds, the present inventors found that
It has been found that bicycloorthoester compounds having vinylbenzyl groups are highly preferred comonomers. An object of the present invention is to provide a method for producing a new copolymer represented by the following formula [] consisting of a bicycloorthoester compound having a vinylbenzyl group and an ethylenically unsaturated compound, and which can be produced by the method of the present invention. The resulting copolymer can be crosslinked by ring opening of its bicycloorthoester group, and has the excellent property of hardly shrinking or slightly expanding upon crosslinking. (In the formula, A represents a monomer unit composed of at least one ethylenically unsaturated compound, R represents a lower alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, and x and (y represents the mole fraction of each structural unit. The same applies hereinafter.) One monomer to be copolymerized in the method of the present invention is a bicycloorthoester compound represented by the following formula [] having a vinylbenzyl group. . The compound of the above formula [] is 1-alkyl-4-hydroxymethyl-2,
6,7-trioxysabicyclo[2,2,2]octane or the following formula derived from the compound []
It is produced by the reaction of sodium alkoxide and chloromethylstyrene. The compound of formula [] is described in Japanese Patent Application No. 11432/1983 (Japanese Patent Application Laid-open No. 108792/1983) filed by the present applicant, and is a compound of pentaerythritol and a trialkyl compound of the following formula. Produced by dealcoholization reaction with orthoacylate. R-C(OR') ₃ (R is an alkyl group.) The sodium alkoxide of the above formula [] is 1-alkyl-4-hydroxymethyl-2,6,7-trioxabicyclo[2] of the formula []. ,2,
2] Obtained by reacting octane with sodium hydride in a tetrahydrofuran solvent, for example. The vinylbenzyl group-containing compound of the formula [] can generally be produced by a dechlorination reaction in which chloromethylstyrene is reacted with a bicycloorthoester compound of the formula [] according to the following reaction. The above reaction is carried out in a suitable organic solvent such as tetrahydrofuran, dimethyl sulfoxide or usually N,
Approximately 20 ~ in N-dimethylformamide (DMF)
It can be carried out at a temperature of 100°C. The compound of formula [] can be separated and obtained from the above reaction solution by removing the generated sodium chloride etc. by filtration or centrifugation, and then recrystallizing the solution or distilling it under reduced pressure in the presence of a polymerization inhibitor, or by removing the solvent and using methylene chloride. The organic layer is dissolved in a solvent such as toluene, washed with water, dehydrated and dried, the solvent is distilled off, and the residue is recrystallized or distilled under reduced pressure in the presence of a polymerization inhibitor. Copolymerized in the method of the present invention, the formula []
The other monomer constituting the monomer unit A in is an ethylenically unsaturated compound, and any monomer that is copolymerizable with the vinyl monomer can be used. Specific examples thereof include the following compounds. Esters of acrylic acid and methacrylic acid, such as methyl, ethyl, propyl, butyl, benzyl, phenyl, cyclohexyl, phenoxyethyl, acetoxyethyl, hydroxyethyl, 2-
Various esters such as ethylhexyl; styrene and substituted styrenes, such as divinylbenzene, o-, m
- or p-chlorostyrene, m- or p-chloromethylstyrene, α-methylstyrene, p-methoxystyrene, p-dimethylaminostyrene, p
-cyanostyrene, p-nitrostyrene, α-acetoxystyrene, etc.; ethylene, 1,2-dichloroethylene, isobutylene, butadiene, isoprene, chloroprene; vinyl chloride, vinyl acetate,
Vinylidene chloride, allyl chloride, allyl acetate; methyl vinyl ether, ethyl vinyl ether; ethyl vinyl ketone, vinylene carbonate, isopropyl vinyl ketone; N-vinylpyrrolidone, 2
-vinylpyridine, 5-methyl-2-vinylpyridine; acrylonitrile, methacrylonitrile;
Vinyl cinnamate, nitrile cinnamate; vinyl benzoate, allyl benzoate; and unsaturated carboxylic acid anhydrides and their ester derivatives, such as maleic anhydride, itaconic anhydride, citraconic anhydride, diethyl maleate, Diethyl fumarate etc. Among the above-mentioned preferred ethylenically unsaturated compounds that can be used in the method of the present invention are of the following formula: (In the formula, R ₁ is hydrogen or an alkyl group, and R ₂
is -CN, -COOR ₃ , -OCOR ₄ phenyl or a phenyl group having alkyl, halogen or haloalkyl as a substituent, and R ₃ is a substituted or unsubstituted alkyl group, cycloalkyl group, or aryl group, and R ₄ is an alkyl group), anhydrides of maleic acid, itaconic acid, and citraconic acid, and ester derivatives thereof. The copolymerization of the compound of formula [] and the ethylenically unsaturated compound in the method of the present invention can be carried out by conventional radical polymerization means, such as ultraviolet rays, infrared rays, heat or microwaves. In ultraviolet radical polymerization, a photoinitiator is usually used. Suitable photoinitiators include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 4'-isopropyl-2-hydroxy-2
-Methylpropiophenone, 2-hydroxy-2
-Methylpropiophenone, 4,4'-bis(diethylamino)benzophenone, benzophenone,
Methyl-(0-benzoyl)-benzoate, 1
-Phenyl-1,2-propanedione-2-(0
-ethoxycarbonyl)-oxime, 1-phenyl-1,2-propanedione-2-(0-benzoyl)-oxime, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin octyl ether, Carbonyl compounds such as benzyl or diacetyl; anthraquinone or xanthone derivatives such as methylanthraquinone, chloroanthraquinone, chlorothioxanthone, 2-methylthioxanthone or 2-i-propylthioxanthone; diphenyl sulfide, diphenyl disulfide or dithiocarbamate, etc. sulfur compounds; α-chloromethylnaphthalene, anthracene, etc. In the polymerization using infrared rays, heat, or microwaves, any radical initiator can be used as long as it can generate radicals by decomposition. For example, di-tert-butyl peroxide,
Organic peroxides such as 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl hydroperoxide, tert-butylperoxybenzoate; 2,2'-azobisisobutyro Azo compounds such as nitrile; ammonium persulfate,
Persalts such as potassium persulfate can be used. When a catalyst is used, the amount used is generally 0.01 to 10 wt%, preferably 0.1% based on the total amount of monomers.
~5wt% range. Radical polymerization proceeds even at room temperature when irradiated with ultraviolet rays, but in other cases it proceeds smoothly under heating or heating conditions. As the polymerization method, any of bulk, solution, suspension and emulsion polymerization can be employed, but bulk or solution polymerization is usually convenient. When using a solvent, for example, ethers such as dioxane, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated alkanes such as dichloroethylene, ketones such as methyl ethyl ketone, methyl isobutyl ketone, etc. Cellosolves such as methyl cellosolve and ethyl cellosolve are commonly used. The copolymer thus produced according to the present invention is
A solution of this in a solvent in which the resulting copolymer is soluble, such as methylene chloride, dioxane, or dimethylformamide, is added dropwise to a precipitation solvent such as n-hexane or methanol under stirring to copolymerize. Separation and purification can be achieved by repeating the operation of precipitating the combined product several times. In the case of the copolymer according to the present invention, its bicycloorthoester group

[Formula] undergoes a ring-opening polymerization reaction according to a cationic polymerization mechanism, resulting in a crosslinked polymer. This crosslinking is usually initiated using a cationic polymerization catalyst. Examples of cationic polymerization catalysts used for this purpose include BF ₃ ,
Lewis acids such as FeCl ₃ , SnCl ₄ , SbCl ₅ , SbF ₃ , TiCl ₄ ; Coordination compounds of Lewis acids such as BF ₃ OEt ₂ , BF ₃ -aniline complexes, etc. and compounds containing O, S, N, etc. ; Examples include oxonium salts, diazonium salts, carbonium salts, halogen compounds, mixed halogen compounds, and perhalogen acid derivatives of Lewis acids. The amount of catalyst used is preferably in the range of 0.001 to 10 wt% based on the general copolymer to be crosslinked. There are no particular restrictions on polymerization temperature, but it is usually room temperature to 200℃.
It will be held in Further, crosslinking can also be carried out by irradiation with radiation such as electron beams and ultraviolet rays. In the case of ultraviolet irradiation, for example, φ-N+ is used as a cationic polymerization catalyst.
Aromatic diazonium salts such as ≡N・PF ^- ₆ , φ−N+≡N・BF ⁻ ₄ ; Aromatic halonium salts such as φ−I ⁺ −φ・BF ⁻ ₄ ; Aromatic onium salts of Group A elements of the periodic table, such as; Aromatic onium salts of Group A elements of the periodic table, such as;

A dicarbonyl complex compound of an element of group a-a of the periodic table, such as the following formula, may be used. The amount of catalyst used is generally preferably in the range of 0.001 to 10 wt% based on the copolymer to be crosslinked. When the above-mentioned acid anhydride is used as the ethylenically unsaturated monomer, the resulting copolymer can be crosslinked simply by the presence of a small amount of water. In the copolymer produced by the production method of the present invention, if the monomer unit derived from the bicycloorthoester compound of formula [] is present in the copolymer in an amount of about 1 mol%, the volume shrinkage during crosslinking will occur as described above. can be substantially improved, so that the molar ratio y/(x+y) of the monomer units in the above formula [] is 1/100.
It is desirable to copolymerize the ethylenically unsaturated compound and the bicycloorthoester compound of formula [] in an arbitrary ratio ranging from 99/100. However, the presence of more than 50 mol% of bicycloorthoester units not only increases costs but also leads to a decrease in water resistance, so it is more desirable that the y/(x+y) ratio be in the range of about 3/100 to 50/100. . The copolymer in the present invention is
It has the same molecular weight as a normal copolymer obtained by polymerizing ethylenically unsaturated compounds by radical polymerization, and specifically has a weight average molecular weight of 1,000 to 10,000,000. Since the copolymer produced by the method of the present invention has a volume-expanding bicycloorthoester group in the molecule, it exhibits the characteristic that the volume is substantially expanded upon crosslinking and curing. Physical properties such as heat resistance and solvent resistance are improved. Thus,
The copolymer of the present invention eliminates the above-mentioned drawbacks associated with volumetric shrinkage, and can be used in paints with good adhesion that do not cause voids, adhesives that do not cause internal distortion, composite materials and cast materials that require dimensional accuracy, etc. It is extremely useful in the production of For example, an excellent coating film can be obtained by dissolving the copolymer of the present invention in an appropriate solvent and applying it to a substrate surface, and curing the formed coating film by an appropriate crosslinking means. After injection, crosslinking can be performed to obtain improved molded articles. Next, the present invention will be further explained by reference examples and examples. In the following Reference Examples and Examples, the specific gravity of the compounds and polymers was measured by the following method. Measurement method A: Density gradient tube method Using a type B direct-reading specific gravity measuring device (Shibayama Kagaku Kikai Seisakusho), the sample is directly placed in a density gradient tube made with an aqueous potassium carbonate solution, or the sample is formed into a tablet for infrared absorption spectrum measurement. After molding it in a container, it was degassed in an aqueous potassium carbonate solution and then placed in it for measurement. Measurement method B: Measured using an air comparison hydrometer type 930 [manufactured by Beckman Japan Co., Ltd.]. Moreover, the average molecular weight of the polymer was calculated from liquid chromatography analysis (abbreviated as HLC analysis) as a weight average molecular weight in terms of polystyrene. The measurement conditions are as follows. Equipment: HLC-801A manufactured by Toyo Soda Kogyo Co., Ltd. Column: 2 TSK gel-GMH Eluent: Tetrahydrofuran Flow rate: 1 ml/min Reference example 1 1-Methyl-4-vinylbenzyloxymethyl-2,6,7- trioxabicyclo[2,2,
2] Production of octane; Sodium hydride (oil suspension, purity 50%) is placed in a four-necked flask equipped with a stirrer, condenser, nitrogen gas inlet, and dropping funnel.
Take 10.56g (0.22mol), wash the oil with n-hexane, and then add dehydrated tetrahydrofuran.
Add 100 ml of 1-methyl-4-hydroxymethyl-2,6,7-trioxabicyclo[2,2,2]octane (32.0 g (0.20 mol) was added little by little. Next, the temperature was raised to 30°C and stirring was continued for 3 hours, and then 60 ml of dehydrated N,N-dimethylformamide was added, and chloromethylstyrene (m-isomer 60/p-isomer 40
36.6 g (0.24 mol) of molar ratio mixture) was added dropwise over about 30 minutes, reacted for an additional 4 hours, and then left overnight. Next, the precipitate was removed by centrifugation, and the supernatant was desolvented. Add 200ml of toluene to the residue and 200ml of distilled water.
Washed 3 times with Anhydrous magnesium sulfate was added to the toluene layer for dehydration, followed by removal of toluene, yielding 38.9g.
A residue was obtained. The pressure was further reduced to 0.17 mmHg, the bath temperature was raised to 100°C, and unreacted chloromethylstyrene was distilled off to obtain 33.0 g of product. Using preparative liquid chromatography under the following separation conditions,
1-Methyl-4-vinylbenzyloxymethyl-2,6,7-trioxabicyclo[2,2,2]octane was fractionated from the reaction product. Separation conditions: Equipment: HLC-807 manufactured by Toyo Soda Kogyo Co., Ltd. Column: TSK Gel G-3000HG+G-2000HG Eluent: Chloroform Flow rate: 4 ml/min The physical properties of the compound are as follows.・Melting point: 66-70℃ ・Specific gravity: 1.163 (25℃) (Measurement method B) ・IR: 1625cm ^-1 (C=C) 1120cm ^-1 , 1040 ^-1 (C-O-C) 855cm ^-1・NMR (in CDCl ₃ ) δ (ppm); 1.45 (3H, s, -CH ₃ ) 3.19 (2H, s, O-CH ₂ -C) 4.02 (6H, s, C-CH ₂ -O) 4.45 (2H, s, φ-CH ₂ ) 5.2-6.9 (3H, CH ₂ =CH-) 7.0-7.4 (4H, φ-H) Reference example 2 1-ethyl-4-vinylbenzyloxymethyl-2,6,7-trio Kisabicyclo [2, 2,
2] Production of octane; 10.56 g of sodium hydride (oil suspension, purity 50%) was placed in the same apparatus as in Reference Example 1.
(0.22 mol) was taken, and after washing the oil with n-hexane, 100 ml of dehydrated tetrahydrofuran was added, and the flask was cooled with ice water. 1-ethyl-4-hydroxymethyl-2, 6,7-trioxabicyclo[2,2,
2] 35.2 g (0.20 mol) of octane was added little by little. Next, the temperature was raised to 30°C and the reaction was carried out for 3 hours, and then 60 ml of dehydrated N,N-dimethylformamide was added, and 36.6 g (0.24 mol) of chloromethylstyrene (mixture of m-isomer 60/p-isomer 40 molar ratio) was added. was added dropwise over about 30 minutes, reacted for an additional 4 hours, and then left overnight.
Next, the produced precipitate was removed by centrifugation, and the supernatant was desolventized. Add 100ml of toluene to the residue and 100ml of distilled water.
Washed 3 times with Add anhydrous magnesium sulfate to the toluene layer and remove toluene after dehydration to obtain a product of 45.9
I got g. Separation was carried out using preparative liquid chromatography in the same manner as in Reference Example 1 to obtain 1-ethyl-4-vinylbenzyloxymethyl-2,6,7-trioxabicyclo[2,2,2]octane. Its physical property values are as follows.・Melting point: 58-61℃ ・Specific gravity: 1.156 (25℃) (Measurement method B) ・IR: 1625cm ^-1 (CH ₂ = CH-) 1130cm ^-1 , 1053cm ^-1 (C-O-C) 935cm ^-1・NMR (in CDCl ₃ ) δ (ppm); 0.96 (3H, t, -CH ₃ ) 1.71 (2H, q, C - CH ₂ ) 3.20 (2H, s, O - CH ₂ -C) 4.02 (6H, s, φ-CH ₂ ) 4.46 (2H, s, φ-CH ₂ ) 5.2-5.9 (3H, CH ₂ =CH-) 7.1-7.5 (4H, φ-H) Example 1 Styrene 0.92 g (8.8 mmol) , 1.11 g (4 mmol) of the compound obtained in Reference Example 1 (1-methyl-4-vinylbenzyloxymethyl-2,6,7-trioxabicyclo[2,2,2]octane),
20 ml of 1,4-dioxane and 0.059 g of AIBN (azobisisobutyronitrile) were charged into a glass sealed tube and polymerized at 75°C for 24 hours. The obtained solution was dropped into n-hexane with stirring to precipitate a polymer. The precipitate was filtered, dissolved in THF (tetrahydrofuran), and the solution was added dropwise to n-hexane with stirring to precipitate a polymer. This dissolution and precipitation purification using THF-n-hexane was repeated again to obtain 0.85 g of a white powdery copolymer. The specific gravity of this copolymer was 1.145 at 25°C. Note that the specific gravity of the copolymer was determined by measurement method A (the same applies to the following examples). The weight average molecular weight determined by HLC analysis was approximately 25,000. The composition ratio of this copolymer was determined by NMR (nuclear magnetic resonance spectrum) analysis to be δ = 6.0 to 7.2 ppm (φ
-H) and δ=1.1~2.4ppm (-CH ₂ -CH-,
- CH ₃ ) was determined from the peak integral value. In addition, 1120 by IR (infrared absorption spectrum) analysis
Characteristic absorptions of cm ⁻¹ , 1050 cm ⁻¹ (C—O—C), and 857 cm ⁻¹ were observed. The structure of this copolymer is represented by the following formula. In the above formula, y/x+y=28/100, and Q represents the following group. Example 2 0.69 g (8 mmol) of vinyl acetate, 1.11 g of the compound obtained in Reference Example 1 (1-methyl-4-vinylbenzyloxymethyl-2,6,7-trioxabicyclo[2,2,2]octane) (4 mmol) 1,
Using 20ml of 4-dioxane and 0.059g of AIBN,
Polymerization and precipitation purification were carried out in the same manner as in Example 1 to obtain 0.59 g of a white powdery copolymer. The specific gravity of this copolymer was 1.209 at 25°C. The average molecular weight determined by HLC analysis is approximately
It was 31000. The composition ratio of this copolymer was determined by NMR analysis as δ
=4.8~5.3ppm

It was determined from [Formula] and the peak integral value of δ=6.0 to 7.3 ppm (φ-H). In addition, IR analysis revealed that 1730cm ^-1 , 1240cm ^-1 (ester), 1120cm ^-1 , 1050cm ^-1 (C-O-C), 856cm
^-1 characteristic absorption was observed. The structure of this copolymer is represented by the following formula. In the above formula, y/x+y=10/100, and Q represents the same group as in Example 1. Example 3 0.80 g (8 mmol) of methyl methacrylate,
1.16 g (4 mmol) of the compound obtained in Reference Example 2 (1-ethyl-4-vinylbenzyloxymethyl-2,6,7-trioxabicyclo[2,2,2]octane), 20 ml of 1,4-dioxane as well as
Using 0.059 g of AIBN, polymerization and precipitation purification were carried out in the same manner as in Example 1, resulting in 0.63 g of white powdery copolymer.
I got it. The specific gravity of this copolymer is 1.204 at 25℃, and the weight average molecular weight determined by HLC analysis is approximately
It was 48,000. In addition, the composition of the copolymer was determined by NMR analysis, δ=
6.4~7.2ppm (φ-H) and δ=2.7~3.9ppm
It was determined from the peak integral value of (COO-CH ₃ , O-CH ₂ -C). Also, IR analysis showed 1730cm ^-1 (ester), 1125
Characteristic absorptions of cm ⁻¹ , 1055 cm ⁻¹ (C—O—C), and 945 cm ⁻¹ were observed. The structure of this copolymer is represented by the following formula. In the above formula, y/x+y=32/100, and Q' represents the following group. Example 4 0.42 g (8 mmol) of acrylonitrile, 1.16 g of the compound obtained in Reference Example 2 (1-ethyl-4-vinylbenzyloxymethyl-2,6,7-trioxabicyclo[2,2,2]octane) (4 mmol), 1,4-dioxane 20 ml and AIBN 0.059 g
Polymerization and precipitation purification were carried out in the same manner as in Example 1 to obtain 0.65 g of a pale yellow powdery copolymer. The specific gravity of this copolymer is 1.191 at 25℃, and the weight average molecular weight determined by HLC analysis is
It was 36,000. In addition, the composition of the copolymer was determined by elemental analysis. In addition, IR analysis revealed that 2210cm ^-1 (nitrile),
Characteristic absorptions of 1050 cm ^-1 (C-O-C) and 940 cm ^-1 were observed. The structure of this copolymer is represented by the following formula. In the above formula, y/x+y=54/100, and Q' represents the same group as in Example 3. Reference Examples 3 to 6 (Crosslinking of copolymers) The copolymers obtained in Examples 1 to 4 were mixed with about 20 times the amount of 1,1
- Dissolved in dichloroethane, and added BF ₃ OEt ₂ as a cationic polymerization catalyst to this solution at a rate of about
It was added at a ratio of 1 wt% and reacted at 60°C for 20 hours to obtain a crosslinked polymer. The specific gravity of this crosslinked polymer was measured by measurement method A, and the volume change due to crosslinking was calculated using the following formula. Volume change rate (%) = (specific gravity before crosslinking/specific gravity of crosslinked polymer - 1)
×100

[Table] In the above, a positive value of the volume change rate (%) due to crosslinking represents the volume expansion rate (%), and a negative value represents the volume contraction rate (%). As is clear from the above table, the copolymer having a bicycloorthoester group produced by the method of the present invention has very small volumetric shrinkage upon crosslinking.
Or, conversely, it has the remarkable feature of exhibiting volumetric expansion.

[Brief explanation of drawings]

FIG. 1 is an infrared absorption spectrum diagram of the compound obtained in Example 1, and FIG. 2 is an infrared absorption spectrum diagram of the compound obtained in Example 4.

Claims (1)

[Claims] 1. A method for producing a copolymer having a bicycloorthoester group, which comprises copolymerizing a bicycloorthoester compound having a vinylbenzyl group represented by the following general formula and an ethylenically unsaturated compound. . (In the formula, R represents a lower alkyl group.)