JPH07300550A - Melamine resin molding material - Google Patents

Abstract

PURPOSE:To obtain a molding material which can be molded into a large complicated shape by regulating a molding material comprising a melamine resin and a pulp so as to have specific values of disc flow and blister-free time. CONSTITUTION:This material comprises a melamine/formaldehyde resin (which may be a polycondensate with another monomer or may be a blend with another resin) and a pulp (produced from wood or linters). By controlling the degree of polymerization of the melamine resin, the amount of the pulp, and the amount of a curing catalyst, the molding material is regulated so as to have a disc flow (elongation of a specimen formed with a disc test mold according to JIS K 6911) of 100-130mm and a blister-free time (minimum time required for compression molding to give a soup bowl under specific conditions without causing blistering) of 70-110sec, preferably 75-100sec.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly applicable to a molded product such as a coffee server, a flowerpot, a vase having complicated irregularities, a handwasher for a low tank of a flush toilet, other molded products such as a washbasin, a wall surface, etc. A melamine-based resin molding material for molding shaped articles that can form molded articles having irregular asperities such as holes and protrusions for attaching to The present invention relates to a melamine-based resin molding material having free time (hereinafter sometimes referred to as BFT).

[0002]

2. Description of the Related Art Conventionally, melamine resin molding materials have been relatively small, such as dishes, bowls and other tableware, and ashtrays.
Alternatively, although it has been used for molding of a simple shape, it is not easy to mold a large-sized irregularly shaped molded product having irregular asperities, and a blur and color unevenness often occur. This is because the conventional melamine-based resin molding material generally has a small temperature difference between the fluidization temperature and the curing temperature, and the fluidization time, that is, the time from the start of fluidization to the start of curing is extremely short. It is thought that it is difficult to fluidize and spread to every corner of the complicated mold, and it is difficult to heat and pressurize sufficiently.

Several methods are known for improving the moldability of such a melamine-based resin molding material.

One method is to co-condensate melamine with urea or phenol or to blend melamine resin with urea resin or phenol resin for the purpose of lowering the fluidizing temperature of the resin and extending the fluidizing time. In order to achieve the intended purpose, urea or phenol is co-condensed with, for example, about 0.4 mol of melamine to 1 mol of melamine, or melamine is used. It is necessary to blend urea resin or phenol resin with 100 parts by weight of the resin, for example, about 20 parts by weight.

However, according to these methods, the heat resistance and weather resistance of the obtained molded article are lowered, the problem of "formalin elution" occurs when it is used as tableware, and coloring becomes difficult only in a dark color system. It was difficult to avoid problems such as reduced flexibility and poor electrical characteristics.

A method has also been proposed in which a melamine-based resin is blended with a thermoplastic resin such as an acrylic resin or a vinyl chloride-based resin to externally plasticize the melamine-based resin. This tendency was remarkable in colored molded products and dark colored molded products.

[0007]

DISCLOSURE OF THE INVENTION As described above, the present inventors have proposed a melamine-based resin molding material satisfying fluidity at the time of molding which was not sufficient with conventional general melamine-based resin molding materials. A melamine-based resin molding material that can be molded into a melamine-based resin molded product that has an excellent appearance without color unevenness and has the excellent physical properties required for various molded products such as crack resistance and insert resistance. Surprisingly, for example, 100 to 13
We have found that a melamine-based resin molding material with a specific disc flow such as 0 mm and a specific BFT such as 70 to 110 seconds is an outstanding molding material that can solve all of the above problems and completed the present invention. did.

[0008]

The present invention is a melamine-based resin molding material containing a melamine / formaldehyde resin and pulp, wherein the disc flow of the molding material is 1
00-130mm and blister free time 70
The purpose of the present invention is to provide a melamine-based resin molding material characterized by being ~ 110 seconds.

The present invention will be described in detail below.

The melamine / formaldehyde resin (hereinafter sometimes abbreviated as "melamine resin") used in the present invention is excellent in weather resistance, colorability and electric characteristics of the obtained molded product, and particularly in molding. From the viewpoint of the "formalin elution" problem when the product is tableware, it is preferable to use a melamine / formaldehyde resin (hereinafter sometimes abbreviated as melamine resin) obtained by reacting melamine with formaldehyde.

The above melamine-based resin can be obtained by substituting a part of melamine with a melamine cocondensation component capable of cocondensation with the melamine and formaldehyde as long as the above-mentioned characteristics of the obtained molded product are not lost. A melamine / formaldehyde co-condensation resin (hereinafter sometimes abbreviated as melamine co-condensation resin) can also be used.

Examples of such melamine cocondensation components include ureas such as urea, thiourea and ethyleneurea; guanamines such as benzoguanamine, acetoguanamine, formguanamine, phenylacetoguanamine and CTU guanamine; and guanidine. Dicyandiamide,
Other amino compounds such as paratoluene sulfonamide; phenols such as phenol, cresol, xylenol, ethylphenol, butylphenol and bisphenol A; other melamine cocondensation compounds such as xylene and saccharose; and the like. The ingredients of can be used together.

The substitution ratio of the melamine co-condensation component is about 0.2 or less in terms of molar ratio with respect to melamine, from the viewpoint of the goodness of the characteristics of the molded article and the goodness of the surface hardness, heat resistance, stain resistance and the like of the molded article. It is preferable that the weight ratio is about 0.2 or less, particularly the molar ratio is about 0.1 or less and the weight ratio is about 0.1 or less.

Further, the melamine-based resin is a blend of the melamine resin and / or the melamine co-condensation resin, which is a thermosetting or thermoplastic resin other than these, in a range in which the characteristics of the molded article can be maintained. It is also possible to use a melamine / formaldehyde blend resin obtained by blending a resin component for use (hereinafter, may be abbreviated as melamine blend resin).

Examples of the blended resin component include:
Thermosetting resins such as urea resins, guanamine resins, phenolic resins (novolak type, resol type), xylene resins, epoxy resins, alkyd resins, unsaturated polyester resins; vinyl chloride resins, vinyl acetate resins, acrylics Examples thereof include thermoplastic resins such as resin and polyethylene terephthalate resin.

The weight ratio of the blending resin component to the melamine resin and / or the melamine co-condensation resin in the melamine blend resin is about 0.2 or less from the same viewpoint as described above.
Particularly, it is preferably about 0.1 or less.

The above-mentioned melamine resin or melamine co-condensation resin is based on 1 mol of the total amount of melamine or melamine and the above-mentioned melamine co-condensation component which is optionally used.
It is preferred to react from about 1 to 3 moles of formaldehyde, with about 1.4 to about 2.5 moles being particularly preferred. If the molar ratio is less than or equal to the upper limit value, the molded product does not become brittle and excellent properties such as crack resistance are maintained, which is preferable. On the other hand, if the molar ratio is at least the lower limit value, It is preferable that the curing speed of the obtained molding material does not decrease, and the "mold" of the obtained molded product is in a good condition.

The formaldehyde includes compounds such as paraformaldehyde which substantially act as formaldehyde in the reaction with the melamine and the melamine cocondensation component.

Part of the formaldehyde reacts with aldehyde components other than formaldehyde, for example, aliphatic aldehydes such as acetaldehyde; aromatic aldehydes such as benzaldehyde; furfural; and other components for melamine and melamine cocondensation. It can be replaced by the resulting aldehyde compound.

The amount of the aldehyde component other than the above-mentioned formaldehyde is about 1 mol of formaldehyde in view of reactivity with melamine and a component for co-condensation of melamine and the curing rate of the resulting melamine resin and melamine co-condensation resin. It is preferably 0.5 mol or less.

The melamine resin molding material of the present invention usually contains pulp in addition to the melamine resin.

The above-mentioned pulp refers to a chain polymer mainly composed of α-cellulose derived from a cellulose raw material, which is usually used as a raw material for paper, chemical fibers, cellulosic plastics, etc., and is generally industrially used. Fibers made from a cellulose raw material treated with wood or linter are used.

The amount of the pulp to be blended is the melamine resin 1
17-35 parts by weight, especially 22-
It is preferably 33 parts by weight. If the blending amount is not more than the upper limit, it is preferable because the molding properties such as the flow characteristics and the minimum molding pressure characteristics of the obtained molding material are excellent.
If it is at least the lower limit, mechanical strength such as insert resistance and crack resistance of the obtained molded product is excellent, and therefore it is preferable.

Further, the melamine-based resin molding material of the present invention may contain other appropriate compounds depending on the desired purpose, as long as the performance of the molding material is not impaired.

Examples of such formulations include, for example:
Organic or inorganic fillers such as rock wool, glass fiber, synthetic fiber, calcium carbonate, talc, clay, silica, gypsum, glass powder; phthalic anhydride, p-toluenesulfonic acid, p-toluenesulfonic acid triethanolamine Curing catalysts such as salts, 2-aminoethyl sulfonic acid, dimethylaniline sulfonic acid hydrochloride, melamine oxalate, ammonium chloride, ammonium phosphate, dimethyl oxalate, dibenzyl oxalate, dimethyl phthalate, trimethyl phosphate, acetamide, oxamide;

For example, titanium oxide, zinc oxide, zinc sulfide, red iron oxide, dark blue, barium sulfate, iron black, ultramarine blue, carbon black, lithopone, titanium yellow, cobalt blue, Hansa yellow, benzidine yellow, lake red, aniline black, di Oxazine violet,
Inorganic or organic pigments such as quinacridone red, quinacridone violet, naphthol yellow, phthalocyanine blue and phthalocyanine green;

For example, zinc stearate, zinc myristate, aluminum stearate, calcium stearate, butyl stearate, stearyl stearate,
Dioctyl phthalate, caproic acid amide, caprylic acid amide, capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, linoleic acid amide, linolenic acid amide, behenic acid amide, erucic acid amide , Behenolic acid amide, ε-caprolactam, stearyl alcohol, glycerin, polyoxyethylene monostearate, polyoxyethylene monooleate, and the like;

The amount of these compounds used is 100 parts by weight of the melamine resin, with no organic or inorganic filler.
-20 parts by weight, preferably 0-15 parts by weight; curing catalyst 0-2
Parts by weight, preferably 0.01 to 1 parts by weight; inorganic or organic pigments 0 to 7 parts by weight, preferably 0.01 to 5 parts by weight; lubricants or plasticizers 0 to 4 parts by weight, preferably 0.1 to 3 parts by weight; The amount can be exemplified.

The melamine-based resin used in the present invention is, for example, 1 mol of so-called melamine crystal powder, or a total of 1 mol of the melamine and the melamine cocondensation component, for example, a 37% aqueous solution of formaldehyde and / or Alternatively, by reacting in a form such as paraformaldehyde at a reaction molar ratio of about 1 to 2.5 mol of formaldehyde in an aqueous medium at a pH of about 7 to 9, for example, a resin concentration of about 40 to 60% by weight is obtained. Produce an aqueous solution of melamine resin,

Pulp is added to this in an amount of 20 to 50 parts by weight with respect to 100 parts by weight of the melamine resin, kneaded, and dried at a temperature of, for example, about 70 to 100 ° C. A popcorn-like pre-dried product of about 3 to 0.5 cm is prepared, and if necessary, this is mixed with other compounds such as organic or inorganic fillers, curing catalysts, inorganic or organic pigments, and lubricants or plasticizers. If necessary, the powdery melamine-based resin molding material can be obtained by pulverizing with the blended resin component.

A kneader, a co-kneader, or the like can be used as the kneading means for forming the popcorn, and hot air drying, band dryer drying, fluidized drying or the like can be used as the drying means.

The above-mentioned pulverization process can be carried out by means of, for example, an impact hammer mill, a ball mill, a vibration mill, a tower mill or the like. If desired, for example, after preliminarily pulverizing with an impact hammer mill, fine pulverizing with a means such as a ball mill, a vibration mill or a tower mill can be performed.

As the method for producing the powdery melamine resin molding material, the melamine resin aqueous solution produced by the above method is dried by a known method such as vacuum drying or spray drying, and if necessary, the powdery melamine resin is used. In addition, powder pulp, the higher fatty acid amide, and the various compounds used as necessary are added to, for example, a V-type mixer, a super mixer, a Nauter mixer, a tumbler, an omni mixer,
A so-called dry method in which a conventional mixer such as a Henschel mixer, a Loedige mixer, a ribbon blender, a planetary mixer or the like is used for homogeneous mixing can be mentioned.

Further, it is possible to employ a method (wet / dry eclectic method) in which the wet method and the dry method are eclectic. Examples of these methods include a popcorn-shaped pre-dried product, a powder or Solid melamine resin, powder pulp, and the various additives used as necessary, further, if necessary, a method of pulverizing and mixing the blended resin components by the pulverizing means, crushing each of these components in advance, etc. After the powder is formed by the means described above, a method of mixing the powder using the above mixer can be exemplified.

Among these methods, good molding characteristics of the obtained molding material and good balance of appearance (fray, color unevenness, etc.) and physical properties (crack resistance, insert resistance, etc.) of the obtained molding product. From the viewpoint of, the wet method or the wet / dry eclectic method is preferable.

In the melamine-based resin molding material of the present invention, the powdery resin molding material obtained as described above can be granulated by a known method. As such a method, for example, the powdery resin molding material is once prepared by using an extruder,
Kneading by heating with a heating roll machine or the like, a method of re-grinding the obtained preformed product, and, for example, compression of the powdery resin molding material without heating to give a preformed product in a sheet shape, a tablet shape, or the like, Examples thereof include a method of re-grinding this.

The melamine resin molding material of the present invention has a disc flow of 100 to 130 mm and a BFT of 70 to 110.
Seconds, preferably 75 to 100 seconds.

If the value of the above-mentioned disc flow is too small below the above lower limit, it is not preferable because the molding material is difficult to reach every corner of the mold when a mold having a complicated shape is used. on the other hand,
If the value of the disc flow is equal to or less than the above upper limit value, the fluidity of the molding material during molding does not become excessive, burrs do not become too thick, and sink marks do not occur in the molded product, which is preferable. .

On the other hand, if the BFT value is too small below the lower limit, the molding time is too long and the productivity is lowered, which is not preferable. It is not preferable because the curing reaction progresses in the middle of the flow, the fluidity deteriorates, the filling becomes incomplete, and the surface of the molded product is liable to be defective in appearance such as scratches and color unevenness.

The disc flow value and the BFT value are
Degree of condensation of melamine resin in melamine resin molding material,
It can be adjusted appropriately by adjusting the amount of pulp and the amount of curing catalyst. Also, these disc flows and
The BFT value is a value obtained by measurement by the following method.

Measurement of disc flow: A disc test mold shown in JIS K 6911, item 5.3.2 is used. Insert 5g of sample into the center of the mold with mold temperature of 150 ± 3 ° C, using a metal cylinder with an inner diameter of about 50mm and a height of about 10mm, to make the sample into a conical shape and load within 15 seconds 2000kgf And compression-molding with a pressing time of 5 minutes. Measure the major axis and minor axis of the glossy part of the molded disk to 1 mm with a dimension measuring instrument and calculate the average value to determine the elongation (mm) of the sample.

Measurement of BFT: First, a melamine resin molding material is used to compression-mold a soup bowl having a diameter of 4.5 inches and a weight of about 85 g under the following conditions.

Mold temperature Upper mold 165 ° C Lower mold 160 ° C Pressure 180kg / cm ² Degassing time 1 second Molding time 120 seconds

After the lapse of the molding time, the mold is opened and the appearance of the molded product is observed. When foamy blisters are generated on the surface of the molded product, molding is performed under the same conditions as above except that the molding time is extended by 2 seconds. Also, if blistering does not occur, molding is performed under the same conditions as above except that the molding time is shortened by 2 seconds. Molding is repeated in this way, and the BFT of the molding material is taken for a minimum time without blistering.

[0045]

EXAMPLES Hereinafter, several aspects of the present invention will be described in more detail with reference to Examples, Comparative Examples and Reference Examples.

Various test methods used in the above Examples, Comparative Examples and Reference Examples are as follows.

(1) Filling property in cavity Using 780 g of melamine resin molding material preheated to 115 ° C. by a high frequency preheater, the opening (upper surface) 150 × 200 mm, the bottom surface 130 × 180 mm, high 220mm thick and 3mm thick trash can is compression molded.

Press used 200T Hydraulic press Mold temperature Upper mold 165 ° C Lower mold 160 ° C Pressure 160kg / cm ² Degassing time 2 seconds Molding time 120 seconds

The filling state of the molded product is visually determined according to the following evaluation criteria. [Evaluation Criteria] ○ ・ ・ ・ ・ ・ ・ Fully filled. ×: ・ There is an unfilled part.

(2) Mold releasability A trash can similar to that described in the above (1) is compression molded under the same molding conditions, and the ease of separation of the molded product from the mold is determined according to the following evaluation criteria. .

[Evaluation Criteria] ◯: The mold is easily released from the mold. △ ・ ・ ・ ・ ・ ・ Release is a little difficult. × ・ ・ ・ ・ Difficult to release.

(3) Color Mottling Prevention Property Using 180 g of a melamine-based resin molding material preheated to 115 ° C. by a high-frequency preheater, a lunch plate having an elliptical shape with a major axis of 30 cm and a minor axis of 20 cm and a partition in the center is used. Compression molding is performed according to the following method.

The molding material is supplied to a 200T hydraulic press and a mold having an upper and lower mold temperature of 165 ° C., and the upper and lower mold intervals are 5 mm or
At 10mm, 0, 2, 4, 6, 8, 1 respectively
Rest for 0 seconds, then immediately pressurize and gauge pressure 40kg / c
The pressure is maintained at m ² for 2 seconds, and then degassing is performed. Then, the pressure is applied again, and after curing at a gauge pressure of 100 kg / cm ² for 120 seconds, the molded product is taken out and allowed to cool. The state of color unevenness on the surface of 12 molded products of the same sample molded in this way is visually evaluated, and the number of molded products having no color unevenness is used as the evaluation score.

[Evaluation Criteria] ○: The number of molded products having no color unevenness is 7 or more. △ ・ ・ 4 to 6 molded products with no color unevenness. × ・ ・ ・ ・ 3 or less molded products with no color unevenness.

Reference Example 1 Melamine (Oilized Melamine Co., Ltd .; oiled melamine) 2520 g
(20 mol), 2760 g of 37% strength formaldehyde aqueous solution
(34 mol) and 900 g of water were placed in a reactor equipped with a reflux condenser,
The mixture was heated and reacted at 90 ° C. with stirring under the condition of F / M = 1.7. When the cloud point of the melamine resin solution reached 60 ° C., 1.6 g of sodium hydroxide was added and cooled to obtain an aqueous melamine resin solution.

The cloud point used as a guide for the end of the reaction is 5 ml of resin solution, and 45 ml of hot water at about 80 ° C.
Is the temperature at which white turbidity occurs when the mixture is stirred and cooled.

Reference Example 2 To 3,000 g of the melamine resin aqueous solution (solid content: about 50% by weight) obtained in Reference Example 1, 555 g of pulp (about 37 parts by weight based on 100 parts by weight of melamine resin) was added and kneaded with a kneader. After that, this kneaded product is dried with a hot air dryer at 80 ° C for 70 minutes,
A pre-dried popcorn product was obtained.

Reference Example A The aqueous melamine resin solution (solid content: about 50% by weight) obtained in Reference Example 1 was dried at about 200 ° C. with a spray dryer to obtain a powdery melamine resin.

Example 1 1630 g of popcorn-like pre-dried product obtained in Reference Example 2
(8 per 100% by weight of the resulting melamine resin molding material
1.5% by weight) to 370 g of powdered melamine resin of Reference Example A
(18.5% by weight), phthalic anhydride 1.0 g (melamine resin 10
About 0.064 parts by weight to 0 parts by weight) and zinc stearate
20 g (about 13 parts by weight to 100 parts by weight of melamine resin) was added, and further 8 g of titanium oxide (about 0.5 parts by weight to 100 parts by weight of melamine resin) as an inorganic pigment and 0.2 g of phthalocyanine blue (melamine resin as an organic pigment). About 0.013 parts by weight to 100 parts by weight) was added and pulverized with a ball mill for 8 hours to obtain a powdery melamine resin molding material for a blue molded product.

The compounding composition of the obtained molding material is shown in Table 1, and various characteristics of the molding material and various physical properties of the obtained molded product are shown in Table 2.

Example 2 and Comparative Examples 1 to 2 In Example 1, 1630 g of the popcorn-like predried product obtained in Reference Example 2 and the powdery melamine resin of Reference Example A 3
Instead of using 70g, change the usage rate, or
The powdered melamine resin is not used, and the melamine resin 100
A melamine resin molding material was obtained in the same manner as in Example 1 except that the compounding amount of phthalic anhydride was adjusted so that the ratio of the curing catalyst to the weight part was not changed.

Table 1 shows the compounding composition of the obtained molding material, and Table 2 shows various characteristics of the molding material and various physical properties of the obtained molded product.

Comparative Examples 3 to 4 Melt resin molding materials were obtained in the same manner as in Example 1 except that 4 g or 0.2 g of phthalic anhydride was used instead of 1 g of phthalic anhydride.

Table 1 shows the compounding composition of the obtained molding material, and Table 2 shows various characteristics of the molding material and various physical properties of the obtained molded product.

Example 3 In Example 1, 1630 g of the popcorn-like predried product obtained in Reference Example 2 and 370 g of the powdery melamine resin of Reference Example A were used.
A melamine resin molding material was obtained in the same manner as in Example 1 except that 1260 g of a popcorn-like pre-dried product, 640 g of powdered melamine resin, 100 g of powdered pulp and 1.6 g of phthalic anhydride were used instead of and 1 g of phthalic anhydride. .

The compounding composition of the obtained molding material is shown in Table 1, and various characteristics of the molding material and various physical properties of the obtained molded product are shown in Table 2.

[0068]

[Table 1]

[0069]

[Table 2]

[0070]

The melamine resin molding material of the present invention is characterized by containing a melamine / formaldehyde resin and pulp, and having a specific disc flow and a specific blister free time. is there.

The melamine-based resin molding material of the present invention satisfying these requirements is particularly suitable for coffee servers, flower pots,
Molded products with complicated irregularities such as vases, irregular shaped irregularities such as holes and protrusions to be incorporated in other molded products such as hand washers for low tanks of flush toilets, wash basins, etc. It is a molding material suitable for molding deformed shaped articles such as.

[Procedure amendment]

[Submission date] December 10, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

On the other hand, if the BFT value exceeds the upper limit and is too large, it takes a long time for the molding to bring about a decrease in productivity, which is not preferable. It is not preferable because the curing reaction progresses in the middle of the flow, the fluidity deteriorates, the filling becomes incomplete, and the surface of the molded product is liable to be defective in appearance such as scratches and color unevenness.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction content]

Reference Example 1 Melamine (Oilized Melamine Co., Ltd .; oiled melamine) 25
20 g (20 mol), 2760 g (34 mol) of a 37% strength aqueous formaldehyde solution and 1800 g of water were placed in a reactor equipped with a reflux condenser, and heated and reacted at 90 ° C. with stirring under the condition of F / M = 1.7. When the cloud point of the melamine resin solution reached 60 ° C., 1.6 g of sodium hydroxide was added and cooled to obtain an aqueous melamine resin solution.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0057

[Correction method] Change

[Correction content]

The cloud point used as a guide for the end of the reaction means that 0.3 ml of the resin solution is sampled, 4.7 ml of hot water at about 80 ° C. is added to it, and the cloudiness occurs when stirring and cooling. Of temperature.

Claims (1)

[Claims] 1. A melamine-based resin molding material comprising a melamine / formaldehyde-based resin and pulp, comprising:
A melamine-based resin molding material, wherein the molding material has a disc flow of 100 to 130 mm and a blister free time of 70 to 110 seconds.