JPH0586431B2 - - Google Patents

Description

Claim 1 (a) polyphenylene ether and (b) a composition.
Thermoplastic composition having improved resistance to discoloration upon exposure to light, comprising a mixture of an anthrapyridone dye in an amount of 0.001 to 0.2% by weight of the composition and a quinophthalone dye in an amount of 0.001 to 0.5% by weight of the composition . 2 The quinophthalone dye has a structural skeleton which may have a substituent, except for the yellow quinophthalone dye which has a hydroxyl group at the 3' position of the structural skeleton.

The composition according to claim 1, having the following formula: This application claims priority from Application No. 8204181, first filed in the Netherlands on October 29, 1982. FIELD OF THE INVENTION This invention relates to polymer mixtures that do not change color upon exposure to light. BACKGROUND OF THE INVENTION Many polymers have the undesirable property of changing color when exposed to light. Such polymers include polyphenylene ethers, aromatic polyesters such as polybutylene terephthalate and polyethylene terephthalate, and polystyrene, rubber-modified high-impact polystyrene, styrene-acrylonitrile (SAN) copolymers, etc. , styrene-containing (co-) such as acrylonitrile-butadiene-styrene (ABS) polymers
There are polymers, especially the above-mentioned styrene-containing (co)polymers that have become self-extinguishing with the addition of aromatic bromine compounds.
The same applies to polymer mixtures containing one or more of the above polymers. This invention relates to a polyphenylene ether polymer,
It relates to a polymer mixture optionally consisting of a styrene polymer and one or more dyes. Such mixtures and methods for their preparation are described, for example, in U.S. Pat.
No. 3306874, No. 3306875, No. 3257357 and No.
It is found in many patent documents such as No. 3257358. The use of styrene polymers in mixtures of this type is disclosed in U.S. Pat.
It is described in more detail in the specification. These mixtures can be colored by introducing dyes. Generally, articles molded from these mixtures undergo discoloration when exposed to light. This discoloration is probably associated with the yellowing of the polyphenylene ether polymer used. The present invention represents a solution to this problem. DESCRIPTION OF THE INVENTION The polymer mixture according to the invention comprises one or more dyes that compensate for the discoloration of the polymer components upon exposure to light, in that the dyes whiten upon exposure to light. Has characteristics. A structural skeleton in which the polymer mixture may have a substituent, except for the yellow quinophthalone dye which has a hydroxyl group at the 3' position of the structural skeleton.

Good results are obtained when yellow quinophthalone dyes and/or purple anthropyridone dyes are included. Quinophthalone dyes themselves are known, and a list of suitable quinophthalone dyes is available in Helvetia.
Chimica Acta vol 52 fasc 5 (1969) p.1259
-1273, which lists several yellow quinophthalone dyes that do not have a hydroxyl group at the 3' position and are suitable for the purpose of this invention. Quinophthalone dyes with a hydroxyl group in the 3' position are very stable when exposed to light and are therefore not suitable for the purposes of this invention. The use of quinophthalone dyes with 3'-hydroxyl substituents in polymers is known from FR 2 252 372. The yellow quinophthalone dye is preferably 0.001-0.5
The purple anthrapyridone dye is used in an amount of 0.001-0.2% by weight. Solvent Yellow 33 (Color Index No. 47000, Amaplast Yellow Y from American Color & Chemical Co., a quinophthalone dye with no substituents on the quinophthalone skeleton), Solvent Yellow 138 (Paliotol Yellow from BASF) Paliotol Yellow) 1090) and Solvent Red 52 (Color Index No. 68210, Buyer
Ag's Macrolex thread (Macrolex)
Good results were obtained using Red) 5B, an anthrapyridone dye substituted with a halogen atom and one or more aromatic groups and having no hydroxyl group in the 3' position. The invention is based on the recognition of the fact that the yellowing of polyphenylene ether polymers can be compensated for by complete or partial decomposition of the chosen dye upon irradiation with light. Best results are obtained by using a yellow quinophthalone dye with a purple anthrapyridone dye. This combination results in color compensation at wavelengths of about 400 to 600 nanometers, where the polyphenylene ether polymer undergoes a visible color change when exposed to light. A preferred polyphenylene ether polymer for use has the formula:

[Chemical formula] (In the formula, Q is a monovalent substituent, for example, a hydrogen atom,
a hydrocarbon group, a hydrohalogen group having at least two carbon atoms between the halogen atom and the phenyl nucleus, an alkoxy group, or a halogenalkoxy group having at least two carbon atoms between the halogen atom and the phenyl nucleus; , Q' and Q'' are the same as Q or additionally represent a halogen atom, Q, Q' and Q'' do not contain a tertiary alpha carbon atom, and n is 50
In addition to the polyphenylene ether polymer (integer number equal to or greater), the polymer mixture according to the invention preferably also contains a styrene polymer. The styrene polymer may be physically mixed with the polyphenylene ether polymer. The polymer mixture may also consist of a seed copolymer, e.g.
There is one formed by coextrusion of a polyphenylene ether polymer and a styrene polymer. The styrene polymer preferably has at least 25% by weight of the polymer units of the formula

[In the formula, R is a hydrogen atom, a lower alkyl group (for example, carbon number 1 to 6), or a halogen atom, Z is a vinyl group, a hydrogen atom, a chlorine atom, or a lower alkyl group, and P is 0 or 1 is an integer of ~5] is a polymer consisting of a vinyl aromatic compound. Accordingly, "styrenic polymers" as defined above and used in the claims of this patent application include, by way of example, homopolymers such as polystyrene, polychlorostyrene and polypromostyrene, commercially available high impact polystyrene polymers. Rubber modified polystyrene and styrene-acrylonitrile copolymer (SAN), styrene-butadiene copolymer, styrene-acrylonitrile-butadiene terpolymer (ABS), poly-α-methyl-styrene, ethyl vinyl Examples include styrene-containing copolymers such as copolymers of benzene and divinylbenzene. Styrene homopolymers and rubber modified high impact polystyrenes are preferred. The styrene polymer may be used in any amount possible. A weight ratio of polyphenylene ether polymer to styrene polymer varying between 1:99 and 99:1 is used. The weight ratio is preferably 1:5 to 5:1
More preferably, a weight ratio of approximately 1:1 is used. The present invention also requires the addition of one or more specific dyes to other polymers that change color upon exposure to light. Examples of such polymers have already been mentioned above. The dyes added to the polymer mixture according to the invention are yellow quinophthalone dyes and/or purple anthrapyridone dyes. Preferably mixtures of these dyes are used. These dyes have the property of whitening when exposed to light, ie they reflect more in the blue and green spectral range after exposure. They therefore compensate for the yellowing of the polymer components in the polymer mixture, which results in a reduction in reflection in the blue and green range of the visible light spectrum. Additionally, other dyes may be included in the polymer mixture to obtain the desired color. In that case, the term "dye" also includes pigments. Polymer mixtures according to the invention can be prepared by conventional techniques. Furthermore, processing into articles is carried out according to conventional methods. It has been found that the yellow quinophthalone dye and the purple anthropyridone dye can be easily mixed in the polymer mixture and remain unaffected and maintain their color at extrusion temperatures up to 300°C. The polymer mixtures according to the invention can be easily prepared by dry mixing the powders or pulverulent starting materials and then mixing in the viscous state, for example on hot rollers or in an extruder. After cooling, the product obtained is made into particles or pellets. In addition to the above-mentioned components, the polymer mixtures according to the invention can optionally contain additives customary for such mixtures.
Examples of such additives include flame retardants, anti-dripping agents, softeners, antioxidants, stabilizers, reinforcing agents, fillers, dyes, processing aids, impact strength modifiers, etc. Each is used in the usual amounts for the intended purpose. The invention will now be described in more detail with respect to the following specific examples. Example 1 Two polymer mixtures are prepared with the same green color, 1
One is mixture A without a dye according to the invention, and the other is an example containing a mixture of two dyes according to the invention. The mixture is prepared by dry mixing the following ingredients.

【table】

[Table] The pigment itself is sufficiently stable even when heated or exposed to light. The total amount of pigment is almost equal in both mixtures. The mutual ratio of the pigments is different in order to give both mixtures the same green color. The mixture is passed through an extruder (approximately 290°C). The extruded material is processed into pellets. Pellets are 50x
It is processed into a test plate with a size of 50 x 3 mm. The test plate was placed in a Suntest apparatus (Original Hanau Quarzlampen GmbH) and exposed to xenon filtered light (daylight D65).
Irradiate for 300 hours. The discoloration compared to the non-irradiated test plate was determined from the reflectance spectrum obtained by a Zeiss RFC3 spectrophotometer using CIELAB (DIB
6174). The test panel obtained from mixture A shows a strong discoloration (delta E _ab *=8.3), and the test panel obtained from the mixture according to the invention shows a very small discoloration (delta E _ab *=2.1). EXAMPLE Two polymer mixtures are prepared in the same beige color, one mixture B without dye according to the invention
and other examples containing mixtures of two dyes according to the invention.

【table】

Table Test plates of mixture B and are prepared by the same method as described in the examples. The board is exposed to light for only 200 hours. The test plates of the polymer mixture according to the invention showed a slight discoloration (delta E _ab *=
1.8), those of mixture B show strong discoloration (delta
E _ab *=4.6). Examples Two mixtures are prepared from the same components as shown in the examples. Additionally, 5 parts by weight of triphenyl phosphate are added to each mixture (flame retardant). Test plates are made from the resulting mixture and exposed to light for 200 hours.
The color change of the test plate without the dye according to the invention was delta E _ab *=4.4, which was more discolored than the color change of the test plate with the dye according to the invention delta E _ab *=1.9.