JP2889715B2 - Method for producing caprolactone-modified hydroxyalkyl acrylate or methacrylate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing hydroxyalkyl acrylates or methacrylates modified with ε-caprolactone, particularly for improving the abrasion resistance of automobile outer panels and for ε-caprolactone useful as a monomer for topcoat paints. The present invention relates to a method for producing a hydroxyalkyl acrylate or methacrylate modified with caprolactone.

[0002]

2. Description of the Related Art Acrylic paints have weather resistance, chemical resistance,
Because of its excellent properties such as stain resistance and physical properties, it is used in various fields such as automobiles, home appliances, building materials, and various devices.

[0003] Hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate,
A resin obtained by copolymerizing a monomer having a hydroxyl group such as hydroxypropyl methacrylate, etc., does not have sufficient reactivity with the crosslinking agent because the hydroxyl group of the acrylic polyol exists at a position very close to the main chain of the acrylic resin skeleton. Therefore, it has been demanded that the reactivity of the hydroxyl group of the acrylic polyol be further increased as compared with the conventional one.

As a method for achieving this object, ring-opening polymerization of ε-caprolactone to hydroxyalkyl acrylate or methacrylate using stannous halide other than fluorine as a catalyst is useful for the production of lactone-modified acrylic polyol. A method for obtaining a polycaprolactone-modified hydroxyalkyl acrylate or methacrylate is disclosed in JP-B-63-66307. In addition, the same publication discloses, as a conventional technique, a ring-opening polymerization of ε-caprolactone on a substance having a hydroxyl group at 130 to 230 ° C. at 130 to 230 ° C. using a titanium-based catalyst such as tetrabutyl titanate, tetraethyl titanate, or tetrapropyl titanate; Or dibutyltin laurate,
It is described that the reaction was carried out by adding a catalyst of an organotin compound such as dibutyltin oxide, tin octylate and the like.

[0005]

However, when a titanium-based catalyst introduced as a prior art in the above patent publication is used, a by-product such as hydroxyalkyl diacrylate or hydroxyalkyl dimethacrylate is produced, Moreover, since these by-products have a high boiling point and are difficult to separate, when the reaction product containing the by-product is radically copolymerized with another acrylate ester in a solvent, the resulting resin undergoes three-dimensional cross-linking and viscosity May be significantly increased or gelled. Moreover, when a titanium-based catalyst is used, there is a disadvantage that the reaction requires a long time.

The process for producing a polycaprolactone-modified hydroxyalkyl acrylate or methacrylate of the invention disclosed in Japanese Patent Publication No. 63-66307 is disclosed at a low temperature of 80 to 130 ° C. and with a small amount of catalyst. Although the reaction proceeds sufficiently and the amount of diacrylate or dimethacrylate by-produced by transesterification is small, there is a problem in that the reaction requires a long time.

In view of the above-mentioned situation, the inventors of the present invention carry out ring-opening polymerization of ε-caprolactone with hydroxyalkyl acrylate or methacrylate to convert caprolactone-modified hydroxyalkyl acrylate or methacrylate in a short time. As a result of intensive studies on a method for efficiently producing the present invention, the present invention has been reached.

[0008]

The gist of the present invention is to produce a caprolactone-modified hydroxyalkyl acrylate or methacrylate by ring-opening polymerization of hydroxyalkyl acrylate or methacrylate with ε-caprolactone. In doing so,
Monomer of tetra-n-butoxytitanium as a ring-opening polymerization catalyst
A caprolactone-modified hydroxyalkyl acrylate or methacrylic acid characterized in that a ring-opening polymerization reaction is carried out at a temperature of 80 ° C. or more and less than 130 ° C. for 3 to 8 hours, and then the reaction product is treated with activated carbon using 20 to 100 ppm based on the total amount. The method for producing acid esters.

The hydroxyalkyl acrylate or methacrylate usable in the present invention includes 2
-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 1,4-butylene glycol mono (meth) acrylate, and the like. (Meth) acrylic acid esters are preferred.

The ε-caprolactone to be subjected to ring-opening polymerization of these esters can be charged in the range of 1 to 8 mol per mol of hydroxyalkyl allyl ester or hydroxyalkyl methacrylate. The degree of polymerization of the modified caprolactone can be controlled by the number of moles of ε-caprolactone to be charged. If the reaction amount of ε-caprolactone is large, the product is solidified when cooled, and the operation becomes difficult, which is not preferable.

In the present invention, ring opening of ε-caprolactone
The catalyst used for the polymerization reaction is tetra-n-butoxytitanium .
is there.

[0012] Tetra n-butoxyti used as a catalyst
The amount of tan added is 20 to the total amount of monomers used in the reaction.
-100 ppm, preferably 20-50 ppm. If the addition amount exceeds 100 ppm, the coloring of the product is remarkable, and even if the next activated carbon treatment is performed, the effect tends to be hardly observed. On the other hand, if the amount is less than 20 ppm, the reaction rate becomes extremely slow, and the ring-opening polymerization reaction requires a long time.

The ring-opening polymerization temperature of ε-caprolactone is 80 ° C. or higher and lower than 130 ° C., preferably 100 ° C.
１２８128 ° C. Even if the ring-opening polymerization reaction is carried out at a temperature lower than 80 ° C., the reaction is undesirably slow and requires a long time.
Further, when a ring-opening polymerization reaction is carried out at a temperature of 130 ° C. or more, the acrylic acid ester itself easily undergoes thermal polymerization, and it becomes difficult to obtain a desired reactant.

The ring-opening polymerization reaction time is 3 to 8 hours, preferably 3 to 6 hours. In the present invention, since the activated carbon treatment is performed after the ring-opening polymerization reaction, the ring-opening polymerization reaction time is relatively short so that the desired reactant can be obtained sufficiently.

It is preferable to add a polymerization inhibitor to the reaction system. Hydroquinone,
An appropriate amount of a usual one such as hydroquinone monomethyl ether is used.

In the present invention, the ring-opening polymerization reaction product is then treated with activated carbon. Examples of the activated carbon include powdered activated carbon and granulated activated carbon, and these are used as appropriate. The amount of activated carbon used is in the range of 0.5 to 5% by weight, preferably 1 to 3% by weight, based on the weight of the ring-opening polymerization reaction product before the activated carbon treatment. Even if the amount exceeds 5% by weight, no further effect can be expected by the activated carbon treatment. If the amount is less than 0.5% by weight, the effect of the activated carbon treatment cannot be obtained, and the ring-opening polymerization reaction of ε-caprolactone must be performed for a long time.

The activated carbon treatment temperature is 60 to 100 ° C., preferably 70 to 90 ° C. After the ring-opening polymerization reaction product is treated with activated carbon, it is filtered to obtain the desired caprolactone-modified acrylate or methacrylate.

The hydroxyalkyl acrylate or methacrylate modified with ε-caprolactone according to the method of the present invention can be used as a monomer for paints of automobiles, various home appliances, various machines, building materials, etc. It is extremely useful as a monomer for improving paintability and top coat.

[0019]

The present invention will be described below in detail with reference to examples. In addition, "part" means "part by weight". The number of colors (APHA) in Examples and Comparative Examples is based on JIS K 6716.
The values measured by the method according to the above are shown.

Example 1 and Comparative Example 1
2 in a four-necked flask equipped with a thermometer, cooling tube and stirrer
910 parts of hydroxyethyl methacrylate, 1596 parts of ε-caprolactone, and 100 ppm of hydroquinone monomethyl ether as a polymerization inhibitor based on the total amount of monomers.
Then, 100 ppm of tetra-n-butoxytitanium was added as a reaction catalyst to the total amount of the monomers, and the mixture was reacted at 120 ° C. for 5 hours while stirring while passing air. A part of the obtained reaction product, caprolactone-modified 2-hydroxyethyl methacrylate, was taken and its color number (APHA) was measured.
00. When this reaction product was left at 50 ° C. for 30 days, the color number (APHA) was 500.

Next, 1% by weight of granulated activated carbon based on the weight of the caprolactone-modified 2-hydroxyethyl methacrylate was added to the caprolactone-modified 2-hydroxyethyl methacrylate as a reaction product after the reaction at 120 ° C. for 5 hours, and the mixture was heated to 80 ° C. For 1 hour and then filtered. The color number (APHA) of the activated carbon-treated caprolactone-modified 2-hydroxyethyl methacrylate was 100. In addition, this product is 30 ° C at 50 ° C.
The number of colors (APHA) after standing for 100 days was 100
Met. Table 1 shows the results.

[0022]

[Table 1]

[0023] Example 2, Comparative Example 2 Example 2-hydroxyethyl methacrylate 910 parts on the same four-necked flask as used in 1, .epsilon.-caprolactone 1596 parts of hydroquinone monomethyl ether as a polymerization inhibitor 100 ppm with respect to the total amount of the monomer, and 30 ppm with respect to the total amount of the monomer, tetra-n-butoxytitanium as a reaction catalyst were added.
The reaction was performed at 4 ° C. for 4 hours. A part of the obtained reaction product, caprolactone-modified 2- hydroxyethyl methacrylate, was taken and its color number (APHA) was measured to be 120. The color number (APHA) of the reaction product left at 50 ° C. for 14 days was 175, and the color number (APHA) of the reaction product left at 50 ° C. for 30 days was 250.

On the other hand, 1% by weight of granulated activated carbon based on the weight of caprolactone-modified 2-hydroxyethyl methacrylate was added to the caprolactone-modified 2-hydroxyethyl methacrylate as a reaction product after the reaction at 120 ° C. for 4 hours. For 1 hour and then filtered. The color number (APHA) of the activated carbon-treated caprolactone-modified 2-hydroxyethyl methacrylate was measured to be 80. In addition, this treated product is heated at 50 ° C for 1 hour.
The number of colors (APHA) when left for 4 days was 80. Further, the number of colors when left at 50 ° C. for 30 days (AP
HA) was also 80.

Further, 1% by weight of granulated activated carbon based on the weight of the treated product was added to the above-mentioned treated product of activated carbon, and a second activated carbon treatment was performed at 80 ° C. for 1 hour, followed by filtration. The color number (APHA) of the second activated carbon product was 80. The number of colors (APHA) of this product when left at 50 ° C. for 14 days and the number of colors (APHA) after further standing at 50 ° C. for 30 days are 80, and the number of colors (APHA) is very low. And excellent storage stability. Table 2 shows the results.

[0026]

[Table 2]

[0027]

According to the present invention, a ring-opening polymerization reaction is carried out using a titanium compound as a ring-opening polymerization catalyst for ε-caprolactone, and furthermore, the obtained reaction product is treated with activated carbon to combine the two steps. It is possible to carry out the ring-opening polymerization reaction at a lower temperature, in a shorter time, and at a higher conversion of ε-caprolactone, compared to the ring-opening polymerization reaction using a titanium compound as a conventional ring-opening polymerization catalyst. it can. The resulting caprolactone-modified acrylate or methacrylate has good hue and excellent storage stability, is particularly useful as a monomer for coating materials, and has remarkable industrial value.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) C07C 69/54 C07C 67/29 B01J 21/06 CA (STN) REGISTRY (STN) WPIDS (STN)

Claims (2)

(57) [Claims] 1. A The ε- caprolactone hydroxyalkyl acrylate or methacrylate by ring-opening polymerization, upon producing the caprolactone-modified hydroxyalkyl acrylates or methacrylates, tetra-n- butoxy ring-opening polymerization catalyst To
A caprolactone-modified hydroxyalkyl acrylate or methacrylic acid, wherein the ring-opening polymerization reaction is carried out at a temperature of 80 ° C. or more and less than 130 ° C. for 3 to 8 hours, using 20 to 100 ppm based on the total amount of the monomers , and then the reaction product is treated with activated carbon. A method for producing an acid ester. 2. The amount of activated carbon to be used is from 0.5 to the amount of the reactant.
The caprolactone-modified hydroxy according to claim 1, which is 5% by weight.
Silalkyl acrylate or methacrylate
Manufacturing method .