JPH0647630B2 - Method for manufacturing resin molded product - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a resin molded product, and more particularly to a method for producing a resin molded product in which only a desired portion can have a crosslinked structure.

(Prior Art and Problems) Conventional resin moldings are roughly classified into moldings made of a thermoplastic resin and moldings made of a thermosetting resin.

A thermoplastic resin molded product is obtained by making a thermoplastic resin fluid by heating to shape it into an arbitrary shape, and then cooling it to fix the shape. It is possible to easily manufacture molded products, and they are currently produced in large quantities. Therefore, thermoplastic resin moldings are very easy to manufacture and are inexpensive, and since those moldings are easily softened by reheating, they can be easily processed after molding, and their surface is further affected by the action of a solvent. It has a number of advantages such as being easy to receive and easy to print and adhere. Many of these advantages include, for example, polyethylene, polypropylene, polystyrene,
AS, ABS, polyester, polyamide, polyurethane and the like are widely used for general purposes.

The drawbacks of the thermoplastic resin molded product as described above are the inside out of the above advantages, and since it is a thermoplastic resin, heat resistance, solvent resistance, abrasion resistance, chemical resistance, compression resistance, etc. It is well known that its physical properties are inferior. Therefore, aside from general applications, in industrial applications where various strict performances such as those mentioned above are required, the use is remarkably limited, and special and expensive polyamides, polyimides, polyesters, engineering plastics such as polycarbonates, etc. Have been used, but none of them solve the above drawbacks sufficiently.

On the other hand, a thermosetting resin molded article shows plasticity before or during molding, but the resin produces a three-dimensional crosslinked structure by heating during molding, and thereafter becomes an insoluble and infusible molded article. Therefore, it solves many of the drawbacks of the above-mentioned thermoplastic resin molded products and is widely used in the industrial field where physical properties such as heat resistance, chemical resistance and compression resistance are required.

As such a thermosetting resin, many ones such as a phenol resin, a melamine resin, an epoxy resin are known, but the drawbacks of a molded article made of such a thermosetting resin are:
First of all, the molding method is limited to the press molding method, the compression molding method, etc., and the curing is too fast during molding,
There are many problems in the process such as being too slow, and it is remarkably inferior in moldability as compared with the thermoplastic resin molded product. Further, regarding the molded product, since the entire molded product is insoluble and infusible, there are drawbacks that processing after molding is almost impossible, and it is difficult to print or adhere to the surface.

Therefore, it is ideal and desired to have a molded product which is easy to mold like a thermoplastic resin at the time of molding and exhibits excellent performances of both the thermoplastic resin molded product and the thermosetting resin molded product as in the previous term. .

(Means for Solving Problems) As a result of earnest research to solve the above-mentioned problems of the prior art and to satisfy the above-mentioned demands, the present inventor molded as a thermoplastic resin at the time of molding, and then The present invention has been completed by developing a method in which only a desired portion of a molded article can be crosslinked so as to have the same properties as a thermosetting resin.

That is, the present invention relates to a thermoplastic resin molding having a group capable of reacting with an isocyanate group or a desired portion of the surface of a thermoplastic resin molding containing a compound having two or more groups capable of reacting with an isocyanate group. A method for producing a resin molded product, which comprises allowing a polyisocyanate compound to penetrate into a surface layer of the molded product and reacting the polyisocyanate compound with the above-mentioned reactive group.

As described above, the present invention provides a crosslinked structure by forming a large number of urethane bonds or urea bonds in the thermoplastic resin only in the desired portion of the thermoplastic resin molded article.

The reactive thermoplastic resin which can be used in the present invention includes a group having a group capable of reacting with an isocyanate group in its structure, for example, a hydroxyl group, a carboxyl group, an amino group, a urethane bond, a urea bond or the like having active hydrogen. Any resin can be used, and examples of the thermoplastic resin having such a group as it is, include a polyurethane resin, a polyamide resin, a polyester resin, an acrylic resin, and a cellulose resin. .

In such a thermoplastic resin, it is also possible to introduce a large number of reactive groups into the resin by copolymerizing a comonomer having a group capable of reacting with an isocyanate group during the production thereof.

Further, like polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyvinyl chloride resins, AS, ABS resins, vinyl acetate resins, polycarbonate resins, acetyl cellulose resins, etc.
In general, even in the case of a thermoplastic resin having no reactive group, a reactive thermoplastic resin can be obtained by copolymerizing a monomer having a reactive group at the time of its production.

Further, in the case of a thermoplastic resin having no reactivity as described above, the method of the present invention can be carried out by incorporating a compound having two or more groups capable of reacting with an isocyanate group, that is, a group having active hydrogen. It can be carried out.

Such a reactive compound may be a reactive thermoplastic resin as described above, a low molecular weight polyol, a polyamine, a polycarboxylic acid, or the like, a polyester polyol, a polyether polyol, a polyester polycarboxylic acid. It may be an oligomer such as polyamide polyamine.

Preferred low molecular weight reactive compounds include, for example, ethylene glycol, 1,4-butanediol,
1,6-hexanediol, 1,5-naphthylene-di-
β-dihydroxyethyl ether, hydroquinone-β-
Low molecular weight polyol compounds such as dihydroxyethyl ether, trimethylolpropane, glycerin and hexanetriol; for example, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, 3,3′-dichlorobenzidine, 3,3′-dichloro- Low molecular weight polyamines such as 4,4′-diaminodiphenylmethane and 2,5-dichlorophenylene-1,4-diamine; for example, amino-ethyl alcohol, 3-amino-chlorohexanol, p-aminophenyl-ethyl alcohol and the like. Low molecular weight amino alcohols; for example, oxalic acid, malonic acid, succinic acid, glutaric acid,
Low molecular weight fats such as adipic acid, pimelic acid, fumaric acid, maleic acid, methylmaleic acid, methylfumaric acid, itaconic acid, citraconic acid, mesaconic acid, acetylenic acid, malic acid, methylmalic acid, citric acid, isocitric acid, tartaric acid Group polycarboxylic acids; for example, phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid, 1,2,3-benzenetricarboxylic acid,
Aromatic aromatic compounds such as 1,3,5-benzenetricarboxylic acid, pyromellitic acid, benzenehexacarboxylic acid, naphthalenedicarboxylic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, diphenyltetracarboxylic acid, diphenylethertetracarboxylic acid and azobenzenetetracarboxylic acid Polycarboxylic acid; Alternatively, polyester polyol comprising the above polyol and polycarboxylic acid, polyester polycarboxylic acid, polyamide amine comprising the polyamine and polycarboxylic acid, polyamide carboxylic acid, and further the above-mentioned polyol or polyamine as a polymerization initiator Examples thereof include polyether polyols obtained by polymerizing alkylene oxides such as ethylene oxide and propylene oxide.

Further, such a reactive compound is not limited to the above-mentioned low molecular weight compounds, oligomers and the like, and a resin having a group capable of reacting with an isocyanate group, for example, a polyurethane resin, a polyamide resin, a polyester resin, an acrylic resin. Polymer compounds such as resin, melamine resin, urea resin, phenol resin, and alkyd resin may be used.

The reactive compound as described above may be mixed into the thermoplastic resin before molding the thermoplastic resin to obtain a molded product, or a molded product after obtaining the thermoplastic resin molded product. Although it may be permeated only into a desired portion of the above, it is preferable to incorporate it in the thermoplastic resin before molding in the case of a compound that requires a long time for permeation or is difficult. Needless to say, such a reactive compound is not limited to the non-reactive thermoplastic resin and may be included in the reactive thermoplastic resin.

Further, the proportion of such a reactive compound included in the non-reactive thermoplastic resin is 100 g of the thermoplastic resin,
The reactive group is in the range of about 0.0001 mol to 1 mol, and if the concentration is less than 0.0001 mol, the crosslinking density due to the polyisocyanate compound is low, and the object of the present invention cannot be sufficiently achieved. On the other hand, if the amount exceeds 1 mol, it is uneconomical and may adversely affect the physical properties of the molded article.

The polyisocyanate compound used in the present invention is a compound having two or more isocyanate groups, and any polyisocyanate compound used in the conventional technology relating to polyurethane resins can be used. , For example 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and mixtures of both, 4,4-diphenylmethane diisocyanate, m-phenylene diisocyanate, 4,
Aromatic diisocyanates such as 4'-biphenyl diisocyanate and aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate and octamethylene diisocyanate, araliphatic compounds such as xylene diisocyanate, and triisocyanates are 4,4 ', 4 "-Triphenylmethane triisocyanate, 2,4,4'-biphenyl triisocyanate, 2,4,4'-diphenylmethane triisocyanate, etc. Other usable isocyanates include di- or triisocyanates of these and diols or triols. Reaction product with a compound having two or more hydroxyl groups in the molecule, and an addition product or isocyanate having two or more isocyanate groups in the reaction product There is a union, and the like.

The polyisocyanate compounds as described above can be used alone or as a mixture, and as a method for infiltrating such a polyisocyanate compound into a desired portion of a thermoplastic resin molded article, (1) Any method may be used, such as a method of heating and using as a melt, (2) a method of dissolving in a suitable organic solvent and using as a solution, and (3) a method of heating and gasifying to use as a gas.

Particularly preferred polyisocyanate compounds in such methods are relatively low molecular weight polyisocyanate compounds.

The concentration at which such a polyisocyanate compound permeates the thermoplastic resin molding is preferably about 0.1 to 70 parts by weight, and less than 0.1 parts by weight per 100 parts by weight of the molding. If the amount exceeds 70 parts by weight, the crosslinking density is too high and unreacted polyisocyanate compound remains in the molded product, which is not preferable. The permeation amount of such a polyisocyanate compound can be arbitrarily changed according to the desired crosslinking density or the reactive group present in the thermoplastic resin or the reactive compound incorporated therein.

The method of the present invention is carried out by using the above-mentioned materials, and first, an arbitrary molded product is molded from a thermoplastic resin. As the method used for such molding, any conventionally known method for molding a thermoplastic resin can be used. For example, any molding method such as injection molding, extrusion molding, vacuum molding, blow molding, foam molding, slush molding, casting, etc. may be used, and a conventional thermosetting resin such as compression molding or transfer molding may be used. A molding method may be used. Of course, the thermoplastic resin used in such optional molding is a thermoplastic resin having a group capable of reacting with an isocyanate group, a non-reactive thermoplastic resin obtained by mixing a compound having such a reactive group, Such as a thermoplastic resin containing a reactive resin.

Further, the shape of the molded product made of such a thermoplastic resin is not limited at all, and examples thereof include ball joints by injection molding, various bushes, various dust covers, various shock absorbers, brake stoppers, 0-rings, and oil supply. Rings, leaf spring spacers, door lock strikers, various gears, packings, sealing materials, plate materials, pickers, KP holders, urethane balls, various casters, thrust washers, tuner parts, tap water taps, etc. Shoe sole materials for sports shoes, various lifts, heel tops, ski grip materials, snowmobile sprockets, caterpillars,
Sole materials such as military shoes and safety shoes, golf balls, belts, gaskets, plugs, sockets, etc., various conveyor belts by extrusion molding, water containers, containers for glazing, flexible containers, motor oils・ Boiling sachets, transport sheets for powder and granular materials, various kappa, clothing, film extruded products such as tapes, inflation processed products and various tubes, tube extruded products such as various hoses, and underground cables. , Submarine cable, power
Examples thereof include coated extruded products such as communication cables, lead wires, computer wiring, automobile wiring, and various enamel wires, and belt extruded products such as various belts.

Next, a polyisocyanate compound is impregnated into the molded product as described above. The portion into which the polyisocyanate compound permeates may be the entire surface layer of the molded article or a part of the surface layer. For example, in the case where the molded product is a hollow molded product such as a hose, the polyisocyanate compound may be allowed to penetrate the entire surface layer thereof, or may be allowed to penetrate only into the inner surface layer thereof. It seems that it may be allowed to permeate only a part of the surface layer, and the entire surface layer of the molded product or the surface layer part that requires heat resistance, chemical resistance, and other performance required as a thermosetting resin molded product. Can only penetrate. The method of infiltrating is a method of immersing a part or all of the polyisocyanate compound in the melt or solution of the polyisocyanate compound as described above, a method of applying these solutions to a molded article, a method of accelerating permeation using pressure, a polyisocyanate. Any method such as using a compound gas may be used. In particular, when permeating, it is possible to accelerate the permeation of the polyisocyanate compound by heating the liquid or gas of the polyisocyanate compound to a temperature at which the molded product is not damaged, for example, a temperature of about 50 to 200 ° C. it can.

As described above, the polyisocyanate compound penetrates into the desired part of the molded product, but the reaction between the polyisocyanate compound and the reactive group of the thermoplastic resin or the reactive compound added proceeds even at room temperature for a long time. So heating is not an essential condition. However, in general, a molded product impregnated with a polyisocyanate compound is
It is preferable to accelerate the reaction by the isocyanate group, that is, the crosslinking reaction by heating at a suitable temperature of about 0 to 200 ° C. for several minutes to several hours.

As described above, the resin molded product according to the method of the present invention is obtained.

(Operation / Effect) According to the present invention as described above, it is possible to provide a resin molded product having excellent properties of a thermosetting resin in a necessary portion by a general method of molding a thermoplastic resin. Therefore, in the method of the present invention, any molding method can be adopted, and a molded product having an arbitrary shape can be obtained. Furthermore, in the molded product of the present invention, the portion to be processed of the molded product is as it is in the state of the thermoplastic resin. Since the remaining portion and the portion requiring various high physical properties can have a cross-linked structure, it is almost impossible to perform various processing after the molding, as in the thermosetting resin molded article of the prior art. The problem has been resolved.

Further, the molded product according to the method of the present invention has, for example, a thermosetting crosslinked structure only on the surface portion in contact with a chemical, leaving the other portion as a thermoplastic resin having thermoformability, and Since the part and the part of thermoplastic resin are completely integrated, sufficient flexibility and flexibility as a molded product,
It has an advantage that it is a molded article having excellent physical properties such as workability, adhesiveness to other parts, and printability. On the other hand, in the case of the conventional thermoplastic resin molded product or thermosetting resin molded product, such a benefit could not be achieved.

Next, the present invention will be described more specifically with reference to examples. In the text, parts or% are based on weight unless otherwise specified.

Example 1 A thermoplastic polyurethane resin having a urethane bond that reacts with an isocyanate group at a concentration of 0.32 mol / 100 g was used to measure a thickness of 3 mm and an outer diameter of 100 by an injection molding machine.
A disc-shaped packing having a diameter of 40 mm and an inner diameter of 40 mm is manufactured. On the other hand,
4,4'-diphenylmethane diisocyanate at 70 ° C
Heat to melt. The packing is 24g each
Met. Next, this packing is completely immersed in the above-mentioned isocyanate melt for 5 minutes and then pulled up to 80 ° C.
After heating for 10 hours, the weight was measured and found to be 25 g.
Met.

The results of measuring the mechanical properties of the packing before and after immersion are shown in Table 1 below.

As described above, it was found that the packing produced by the method of the present invention has a significantly improved compression set and a crosslinking effect.

Example 2 Using a thermoplastic polyurethane resin having a urethane bond that reacts with an isocyanate group at a concentration of 0.40 mol / 100 g, an outer diameter of 120 mm and an inner diameter of 1 were measured by an injection molding machine.
A hollow hose-shaped molded product having a length of 10 mm and a length of 300 mm is manufactured. Next, both ends of this hose are fused and sealed. The weight of this hose was 207 g. Then, as in Example 1, it was immersed in a melt of 4,4'diphenylmethane diisocyanate at 70 ° C for 10 minutes and then heated at 80 ° C for 1 hour. The weight after immersion and heating was 221 g.

Next, as a result of cutting off the fusion-bonded portions at both ends and observing the inner surface of the hose, it was confirmed that the polyisocyanate compound did not penetrate into the surface portion of the inner surface. Next, an adhesive was applied to the surface of a stainless rod having a diameter of 110 mm, and the roll was manufactured by bonding the adhesive to the inside of the hose with the fused portion cut off. A roll was produced in the same manner except that it was not immersed in the polyisocyanate compound. Table 2 shows the results of practical tests using these rolls as platen rolls for word processors.

Obviously, the dip roll has improved impact resistance due to the cross-linked surface.

Further, since the inside is thermoplastic, the adhesive strength was almost the same as that of the unimmersed roll.

Example 3 70 parts of a heat-resistant ABS resin was mixed with 30 parts of a thermoplastic polyurethane resin having a urethane bond concentration of 0.35 mol / 100 g and kneaded. At this time, the concentration of urethane bonds that react with the isocyanate groups in the kneaded product becomes 0.105 mol / 100 g. Next, the heel top is molded using an injection molding machine. This heel top weighed 1.5 g each. In the same manner as in Example 1, 5 minutes of immersion in 4,4'-diphenylmethane diisocyanate melt at 70 ° C was followed by withdrawing and heating at 90 ° C for 12 hours. Heel top after heating is 1
The number was 1.6 g. Table 3 shows the results of the practical durability test in comparison with the undipped heel top.

Apparently, the dipping-treated heel top had good wear resistance.

Claims (4)

[Claims] 1. A thermoplastic resin molded product having a group capable of reacting with an isocyanate group, or a thermoplastic resin molded product containing a compound having two or more groups capable of reacting with an isocyanate group, is formed from a desired portion of the surface of the thermoplastic resin molded product. A method for producing a resin molded product, which comprises allowing an isocyanate compound to penetrate into a surface layer of the molded product and reacting the polyisocyanate compound with the above-mentioned reactive group. 2. The production method according to claim 1, wherein the thermoplastic resin is a polyurethane resin. 3. The production method according to claim 1, wherein the thermoplastic resin is a non-reactive thermoplastic resin containing a compound containing two or more groups capable of reacting with an isocyanate group. . 4. The production method according to claim 1, wherein the thermoplastic resin is a mixture of a non-reactive thermoplastic resin and a polyurethane resin.