JP2003192798A - Transparent polyamide molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively produce a transparent polyamide molding resistant to ultraviolet inhibitor bleeding and to yellowing. <P>SOLUTION: The transparent polyamide molding is one prepared by compounding and kneading a transparent polyamide resin of a glass transition point of at least 110°C with an ultraviolet absorber, wherein the molding has a chromaticness index b* of at most 12 as measured with a color difference meter. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent polyamide-based molded article having a function of shielding ultraviolet rays while maintaining the transparency, chemical resistance and heat resistance inherent in a transparent polyamide-based molded article.

[0002]

2. Description of the Related Art Transparent polyamide resin is lightweight, tough,
Due to its chemical resistance and heat resistance, it is used in a wide range of fields from industrial parts such as battery cases, oil gauges and breaker housings, to daily necessities such as eyeglass lenses and frames, sunglasses and goggles.
Among these products, it is necessary to protect the sunlight from UV rays with sunglasses and goggles worn by people directly. In addition, the ozone layer has been recently destroyed, and the amount of ultraviolet rays falling on the earth has increased, and among many people, interest in preventing ultraviolet rays has increased.

The ultraviolet absorbers used in transparent polyamide resin products so far tend to bleed out from the products, and the ultraviolet protection effect tends to gradually decrease. Also, conventional UV absorbers tend to color transparent polyamide products in yellow, and sunglasses are often "lightly colored" because they are "fashion products", and transparent polyamide resin colored in yellow gives free "coloring". Was difficult. Therefore, there has been a demand for a transparent polyamide resin which has a permanent anti-UV effect and can be freely colored from a light color to a dark color.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art, and it is possible to inexpensively produce a transparent polyamide-based molded product which does not bleed an ultraviolet ray inhibitor from a transparent polyamide product and is not colored yellow. The problem is to manufacture.

[0005]

Means for Solving the Problems The inventors of the present invention have made earnest studies, studies, and studies in order to solve the above problems, and finally completed the present invention. That is, the present invention has a glass transition point of 1
A transparent polyamide molded product obtained by blending and kneading an ultraviolet absorber in a transparent polyamide resin at 10 ° C. or higher, wherein the molded product has a b * value of 12 or less measured by a color difference meter. . The transparent polyamide molding as described above, wherein the ultraviolet absorber is a hydroxyphenyl triazine compound.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below.
The transparent polyamide resin in the present invention is an amorphous transparent polyamide resin that does not have a clear melting point as measured by a differential scanning calorimeter (DSC), and specifically, 4,4′-diamino-3,3′-dimethylmethyl Cyclo-hexylene methane (CA), 4,4'-diaminodicyclo-hexylene methane (P
ACM), metaxylylenediamine (MXD), trimethyl-hexamethylenediamine (TMD), isophorone diamine (IA), 4,4 'diaminodicyclodihexylpropene (PACP) and other diamines and terephthalic acid, isophthalic acid Examples thereof include, but are not limited to, polymers or copolymers or blends obtained by polycondensation of dicarboxylic acids such as adipic acid sebacic acid and dodecane diacid and lactams such as caprolactam and lauryllactam. It is not something that will be done.

In the present invention, the transparent polyamide resin having a number average molecular weight of 7,000 to 30,000 is preferably used. When the number average molecular weight is 7,000 or less, the toughness decreases, which is not preferable. Further, if it is 30,000 or more, the fluidity is lowered, which is not preferable. The glass transition point of the transparent polyamide resin in the present invention needs to be 110 ° C. or higher. When the glass transition point is lower than 110 ° C., the heat resistance of the transparent polyamide resin is not sufficient, and the glass transition point is further lowered by moisture absorption, which is not preferable for practical use.

The ultraviolet absorber in the present invention is an additive that absorbs sunlight having a wavelength of 400 ± 20 nm or less. In the present invention, the ultraviolet absorber has a high ultraviolet shielding ability and a low volatility, and a polyamide resin. Those having excellent compatibility with are preferable, and among them, hydroxyphenyl-triazine-based UV absorbers are preferable, and 2- (4,6
-Diphenyl-1,3,5 triazin-2-yl) -5 [(hexyl) oxy] -phenol, 2-
(4,6-Diphenyl-1,3,5 triazine-2-yl) -5 [(heposyl) oxy] -phenol, 2- (4,6-diphenyl-1,3,5 triazine-2-yl) -5 [(octyl ) Oxy] -phenol, 2- (4,6-diphenyl-1,3,5triazine-2-yl) -5 [(nonacyl) oxy] -phenol, 2- (4,6-
Diphenyl-1,3,5 triazin-2-yl) -5 [(decasil) oxy] -phenol and the like can be mentioned.

This hydroxyphenyl-triazine type ultraviolet absorber has a high ability to shield ultraviolet rays, a low volatility, and an excellent compatibility with a polyamide resin. Therefore, even if it is blended with the transparent polyamide resin and kneaded at a high temperature, the ultraviolet absorber does not decompose or scatter, and the compatibility with the polyamide resin is good, so that uniform dispersion is possible. The transparent polyamide-based molded product containing the ultraviolet absorber does not have yellow coloring and the ultraviolet absorber does not bleed.
The amount of the ultraviolet absorber compounded is 0.02 to 8.0 parts by weight, preferably 0.05 to 5.0 parts by weight, based on 100 parts by weight of the transparent polyamide resin. If the amount of the ultraviolet absorber is less than 0.02 parts by weight, the ultraviolet absorbing effect is small, and if it exceeds 8.0 parts by weight, it is not economical.

In the present invention, the b * value representing the degree of coloring of the transparent polyamide molding is important. The b * value in the L * a * b * color space determined by the CIE (International Commission on Illumination) indicates that when this value is large, it is colored yellow. In the present invention, the transparent polyamide-based molded product has ab * value of 12
It is the following. If the b * value exceeds this value, it is not possible to freely tint light colors for fashion products such as sunglasses lenses, resulting in a decrease in commercial value.

In the present invention, a release agent, a lubricant, a heat stabilizer, an antistatic agent, a dye, a pigment, a weather resistance improver, an antioxidant and the like can be blended within a range that does not impair the characteristics of the transparent polyamide molding.

The transparent polyamide-based molded product of the present invention is obtained by blending and kneading a transparent polyamide resin with an ultraviolet absorber and other necessary additives. The kneading device is not particularly limited, and a general single-screw extruder, a twin-screw extruder, a pressure kneader, or the like is used. Of these, a twin-screw extruder is particularly preferable. Kneading temperature is 230 ℃ ~ 300 ℃
The kneading time is generally about 2 to 15 minutes.

The transparent polyamide-based molded product according to the present invention is a molded product which has excellent properties such as lightness, chemical resistance, toughness, heat resistance and the like of the transparent polyamide resin, as well as extremely good ultraviolet absorption properties and does not turn yellow. Can be obtained.

[0014]

EXAMPLES Next, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited thereto. Examples 1 to 3 Comparative Examples 1 and 2 Examples of the transparent polyamide resin include grillamide TR-55 (Ems Co., a polymer of isophthalic acid / CA / lauryl tacrum), trogamide T (Dynamite Nobel Co., Ltd.),
Polymer of terephthalic acid / TMD). UV absorber is Tinuvin 1577FF as hydroxyphenyl-triazine type
(Ciba-Geigy Co., Ltd.) and benzotriazole-based UV absorber Tinuvin 234 (Ciba-Geigy Co., Ltd.) were used. 0.8 parts by weight of each of these ultraviolet absorbers was added to 100 parts by weight of the transparent polyamide resin. The kneading was carried out with a twin-screw extruder at a temperature of 280 ° C. to prepare pellets. Molding is performed with an injection molding machine at a cylinder temperature of 280 ° C and a mold temperature of 7
A flat plate having a thickness of 2 mm was molded at 0 ° C. and used as an evaluation sample.

The evaluation sample has a glass transition point (Tg) as a material property measured by DSC. The ultraviolet absorptivity was evaluated by measuring the spectral transmittance (%) at 400 nm from the spectral transmittance curve of the transparent plate. The b * value was measured by a color difference meter. Further, the presence or absence of bleeding of the ultraviolet absorbent from the molded product was evaluated by leaving the evaluation sample in a thermostat at 30 ° C. and 95% RH for one week, and observing the surface of the sample taken out. The results are shown in Table 1.

[0016]

[Table 1]

[0017]

As is clear from Table 1, in Example 1, the ultraviolet transmittance was low, the b * value showing the yellowness of the molded product was small, and the bleeding of the ultraviolet absorber did not occur. On the other hand, Comparative Example 1 has no ultraviolet ray shielding effect. Comparative Example 2
In the case, the coloration of the molded product is large, and bleeding of the ultraviolet absorber has occurred. In Example 2, even with different kinds of transparent polyamide resins, extremely excellent characteristics can be obtained as in Example 1. On the other hand, in Comparative Example 2, coloring and bleeding of the molded product occur, and the commercial value of the transparent polyamide-based molded product is significantly reduced. Therefore, in addition to the characteristics of the polyamide resin such as the lightweight polyamide, the chemical resistance, the toughness and the heat resistance, the transparent polyamide-based molded product of the present invention has an excellent ultraviolet shielding effect and can be freely colored in any coloring. It can be used for a wide range of applications, from industrial parts to fashionable products, such as sunglasses and its lenses, eyeglass frames and lenses, goggles, sun visors, anti-UV window glass with a focus on fashion, and welding protection glasses. So it is great to contribute to industry.

Claims (2)

[Claims] 1. A transparent polyamide-based molded article obtained by blending and kneading a transparent polyamide resin having a glass transition point of 110 ° C. or higher with an ultraviolet absorber, and using a color difference meter of the molded article.
* A transparent polyamide-based molded product characterized by a value of 12 or less. 2. The transparent polyamide molding according to claim 1, wherein the ultraviolet absorber is a hydroxyphenyl triazine compound.