JPH08100079A - Crosslinking agent - Google Patents

Abstract

PURPOSE: To obtain a crosslinking agent with which a substance having a functional group reactive with a glycidyl ether group is crosslinked to give a crosslinked product having intact hardness and strength and excellent flexibility by using a glycidyl ether of a specific compound. CONSTITUTION: This crosslinking agent comprises a glycidyl ether of a propylene oxide adduct to a sugar, preferably a sugar alcohol or glycoside (e.g. sorbitol). It is obtained by the addition reaction of a sugar with propylene oxide so that preferably at least three propylene oxide molecules are bonded to two or more hydroxyl groups of the sugar and that the number of moles of the propylene oxide bonded is 3-30, preferably 4-20, per mol of the sugar, an then converting two or more, desirably three or more, preferably four or more, per molecule of the hydroxyl groups of the adduct into glycidyl ether groups. The resultant glycidyl ether preferably has an epoxy equivalent of 120-450g/eq.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a crosslinking agent. More specifically, the present invention relates to a cross-linking agent which can be used in a wide range of fields such as paints, adhesives, molded plastic products and rubber.

[0002]

2. Description of the Related Art Conventionally, polyhydric alcohol glycidyl ether has been known as a cross-linking agent for improving the mechanical properties, heat resistance and durability of paints, adhesives, plastic molded products, rubbers, etc. Furthermore, glycidyl ethers of sugars such as sorbitol are known.

[0003]

However, none of them have sufficient flexibility, and they have the drawback of being brittle because they have hardness but poor flexibility.

[0004]

The present inventors have arrived at the present invention as a result of extensive studies for the purpose of obtaining a cross-linking agent which yields a cross-linked product having flexibility and impact resistance. That is, the present invention is a cross-linking agent comprising a glycidyl etherified product of a propylene oxide adduct of sugar.

In the present invention, saccharides are monosaccharides, oligosaccharides,
Sugar alcohols, such as glucosides, monosaccharides such as glucose, mannose, fructose, sorbose, etc., oligosaccharides such as sucrose, crehalose, lactose, raffinose, and sugar alcohols such as adonitol, arabitol, xylitol, etc. Hexitol such as pentitol, sorbitol, mannitol, iditol, taritol, dulcitol and the like, and examples of the glucoside include methyl glucoside, butyl glucoside and the like. Of these, sorbitol and methyl glucoside are preferable.

In the present invention, the propylene oxide adduct of a saccharide is one in which propylene oxide is added to at least two hydroxyl groups of the saccharide, preferably 3
Propylene oxide is added to more than one.
The number of moles of propylene oxide added per mole of saccharide is usually 3 to 30 moles, preferably 4 to 20 moles. If it is less than 3 mol, the flexibility cannot be fully exhibited. On the other hand, if it exceeds 30 moles, a sufficient crosslink density cannot be obtained and the strength of the crosslinked product becomes weak.

In the present invention, in the glycidyl ether compound, two or more hydroxyl groups in one molecule of the propylene oxide adduct of sugar are glycidyl etherified, preferably 3 or more, more preferably 4 or more. The hydroxyl groups of are glycidyl etherified. The glycidyl etherification of only one hydroxyl group does not contribute to the crosslinking reaction.

The epoxy equivalent of the glycidyl ether compound is usually 120 to 450 g / eq, preferably 15
It is 0 to 300 g / eq. Epoxy equivalent is 120 g /
If it is less than eq, the flexibility cannot be sufficiently exhibited. Also, 4
If it exceeds 50 g / eq, a sufficient crosslink density cannot be obtained and the strength of the crosslinked product becomes weak.

The glycidyl ether compound is a saccharide and NaO.
It can be obtained by addition-polymerizing propylene oxide in the presence of an alkali such as H or KOH, and further subjecting to glycidyl etherification with epihalogenohydrin such as epichlorohydrin.

The glycidyl etherification reaction can be carried out by any of the conventionally known one-step method and two-step method. For example, in the one-step method, it can be obtained by reacting a propylene oxide adduct of a sugar with epichlorohydrin at 30 to 120 ° C. in the presence of an alkali such as NaOH or KOH. In the two-stage method, an epichlorohydrin and an ethyl chlorooxide are mixed with an acid catalyst such as boron trifluoride or tin tetrachloride using an alkylene oxide adduct of a sugar as a catalyst.
After reacting at 0 to 100 ° C to obtain a chlorohydrin adduct, an alkali such as NaOH is added to the mixture at 30 to 100 ° C.
It is obtained by dehydrochlorination at. In either method, the produced salt is removed by ordinary filtration or washing with water and purified.

Of the one-step method and the two-step method, the one-step method is preferable because the hydrolyzable chlorine content and the total chlorine content of the purified product are small. When synthesized and purified by the one-step method, the hydrolyzable chlorine content of the crosslinking agent of the present invention is usually 0.5% by weight.
It is below, preferably 0.2% by weight or less. The total chlorine content is usually 1.0% by weight or less, preferably 0.5% by weight or less.

The cross-linking agent of the present invention can be used for cross-linking paints, adhesives, plastic moldings, rubbers, fiber treatment agents, sheets, films, sealants, etc., and has a functional group reactive with a glycidyl ether group. Any substance having a group can be used. Examples of the functional group reactive with a glycidyl ether group include a carboxyl group, an amino group, a hydroxyl group, an acid anhydride group, a methylol group, a silanol group, an aldehyde group, an acetal group, an amide group,
Examples thereof include a thiol group, a halogenated alkyl group, an isocyanate group, an acetoacetate group, an imide group, and a phosphoric acid ester group. Of these, preferred are cross-linking agents for coatings containing as a main component a copolymer containing acrylic acid, methacrylic acid, maleic anhydride, maleic acid, itaconic acid and the like.

Paints to which the crosslinking agent of the present invention is applied,
The equivalent ratio of the above functional groups and glycidyl groups contained in the resin component of adhesives, plastic molded products, etc. is usually 1: 1 to
It is 1: 1.5, preferably 1: 1 to 1: 1.2. If the equivalent ratio of the glycidyl group is less than 1, the unreacted functional group remains and the cured product does not have sufficient physical properties. Alternatively, when the equivalent ratio is 1.5 or more, a reaction with a hydroxyl group generated by the reaction of the glycidyl group may further occur, but an excessive crosslinking reaction undesirably makes the cured product brittle.
The crosslinking agent of the present invention can be used at a temperature ranging from room temperature to 180 ° C., and can be selected depending on the reactivity with the functional group to be crosslinked. Further, if necessary, it can be used in combination with a crosslinking agent other than the present invention.

When using the crosslinking agent of the present invention, if necessary, a crosslinking accelerator, a plasticizer, a filler, a pigment, a processing aid,
Antiaging agents, stabilizers and the like can also be added.

[0015]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.

Production Example 1 Into a 1-liter four-neck reaction flask, a propylene oxide 5 mol adduct of sorbitol (OHV = 730 meq KO) was added.
H / g) and epichlorohydrin (240 g) were charged, solid NaOH (100 g) was gradually added at 60 ° C. with stirring, and the reaction was continued at the same temperature for 5 hours. After cooling
After 310 g of water was added, the mixture was washed with water, and allowed to stand still for liquid separation. When the low boiling point component in the upper layer was removed under reduced pressure and filtered, 150 g of glycidyl ether of propylene oxide 5 mol adduct of sorbitol (crosslinking agent A: epoxy equivalent = 159 g / e
q, hydrolyzable chlorine content 0.08% by weight, total chlorine content 0.21% by weight).

Production Example 2 Propylene oxide 7 mol adduct of methyl glucoside (OHV = 383 meqKOH / g) was placed in the same container as in Production Example 1.
100 g and 210 g of epichlorohydrin were charged, 55 g of solid NaOH was gradually added at 40 ° C. with stirring, and the mixture was stirred at the same temperature for 6 hours. After cooling, toluene 20
After 0 g and 180 g of water were added and the mixture was washed with water, the mixture was left standing and separated. After removing the low boiling point component in the upper layer under reduced pressure and filtering, 130 g of glycidyl ether of propylene oxide adduct of methyl glucoside (crosslinking agent B: epoxy equivalent = 208 g
/ Eq, hydrolyzable chlorine content of 0.05% by weight, total chlorine content of 0.12% by weight).

Example 1 35 parts by weight of methyl methacrylate, 25 parts by weight of n-butyl methacrylate, 10 parts by weight of hydroxyethyl methacrylate, 20 parts by weight of methacrylic acid and 20 parts by weight of styrene and having an average molecular weight of 19000 were obtained. 100 parts by weight of the copolymer, 90 parts by weight of titanium oxide, and 10 parts by weight of the cross-linking agent A obtained in Production Example 1 were premixed with a Henschel mixer, and then melt-kneaded with a two-roll mill at 80 to 90 ° C. This kneaded product was cooled and then finely pulverized to obtain a powder coating material. This powder coating material was coated on a zinc phosphate-treated steel plate by an electrostatic powder coating machine so as to have a film thickness of 40 to 50 μm, and baked at 180 ° C. for 25 minutes in a circulating air dryer to obtain a test plate. . The coating film performance is shown in Table 1.

Examples 2 to 4, Comparative Example 1 100 parts by weight of the copolymer of Example 1 and 100 parts by weight of titanium oxide, and the following cross-linking agent B obtained in the same manner as in Production Example 1
.About.E and the comparative cross-linking agent Y were added to prepare test plates in the same manner as in Example 1. The coating film performance is shown in Table 1.

[0020]

[Table 1] Crosslinking agent A: sorbitol (PO) 5 mol glycidyl ether epoxy equivalent = 159 g / eq Crosslinking agent B: methyl glucoside (PO) 7 mol glycidyl ether epoxy equivalent = 208 g / eq Crosslinking agent C: sorbitol (PO) 7 mol glycidyl ether epoxy Equivalent weight = 188 g / eq Cross-linking agent D: Methyl glucoside (PO) 9 mol glycidyl ether Epoxy equivalent weight = 235 g / eq Comparative cross-linking agent Y: Sorbitol glycidyl ether epoxy equivalent weight = 170 g / eq * 1) Flex resistance: φm / m * 2 ) Impact resistance: DuPont type (1/2 "x 500g) * 3) Goggle test: JIS K-5400 (no peeling 100/100)

As shown in Table 1, it can be seen that the coating film performance of the powder coating material using the crosslinking agent of the present invention is good and can withstand the bending of 4 mm in diameter. In addition, it can be seen from a DuPont type impact resistance test that it can withstand impact from a height of 45 to 55 cm. Also, the surface hardness of the coating film is equal to or higher than that of Comparative Example 1, indicating that the coating film has hardness, flexibility and impact resistance.

Example 5 50 parts by weight of melamine, 20 parts by weight of water, 6 mol glycidyl ether of sorbitol (PO) (crosslinking agent E: epoxy equivalent = 201 g / eq) were placed in a 1-liter three-necked flask.
0 part by weight was charged and reacted at 60 to 80 ° C. for 2 hours. In addition, 30 parts by weight of 37% formalin was added,
The reaction was carried out at 0 ° C for 1 hour. 30 parts by weight of sheet pulp is added to 100 parts by weight of this resin, which is then infiltrated, dried and pulverized, 0.4 parts by weight of phthalic anhydride and 1 part by weight of zinc stearate are added, and mixed and dispersed in a pot mill to obtain a resin molding material. This was compression-molded. Table 2 shows the evaluation results.

Examples 6 to 8 and Comparative Example 2 Instead of the crosslinking agent E in Example 5, the following crosslinking agents F to
A molded product was obtained in the same manner as in Example 5 by using H and the comparative crosslinking agent Y. Table 2 shows the evaluation results.

[0024]

[Table 2] Crosslinking agent E: sorbitol (PO) 6 mol glycidyl ether epoxy equivalent = 171 g / eq Crosslinking agent F: sorbitol (PO) 15 mol glycidyl ether epoxy equivalent = 285 g / eq Crosslinking agent G: methyl glucoside (PO) 12 mol glycidyl ether epoxy Equivalent weight = 248 g / eq Comparative cross-linking agent Y: sorbitol glycidyl ether Epoxy equivalent weight = 170 g / eq * 4) DuPont type (1/2 ″, 500 g) * 5) Charpy impact strength (kgf · cm / cm ² ).

As shown in Table 2, the cured melamine product using the crosslinking agent of the present invention does not decrease in bending strength,
It can be seen that the flexural modulus is lowered and flexibility is imparted as compared with the case of the comparative crosslinking agent Y.

[0026]

The cross-linking agent of the present invention provides a cross-linked product having excellent flexibility. The crosslinking agent of the present invention can impart flexibility without impairing the hardness and strength of the crosslinked product. The cross-linking agent of the present invention having the above effects is useful as a cross-linking agent for applications such as paints, adhesives, plastic molded products, sheets, films, sealants, and fiber treatment agents.

Claims (5)

[Claims] 1. A cross-linking agent comprising a glycidyl etherified product of a propylene oxide adduct of a sugar. 2. The crosslinking agent according to claim 1, wherein the saccharide is sugar alcohol or glucoside. 3. The crosslinking agent according to claim 2, wherein the sugar alcohol is sorbitol. 4. The cross-linking agent according to claim 2, wherein the glucoside is an alkyl glucoside. 5. The crosslinking agent according to any one of claims 1 to 4, wherein the glycidyl ether compound has an epoxy equivalent of 120 to 450 g / eq.