JPH04288387A - Ultraviolet absorber - Google Patents

Abstract

PURPOSE:To obtain the title absorber capable of giving fluororesin excellent ultraviolet absorbing performance by forming from an ultraviolet absorbing copolymer which has a specified weight-average molecular weight and comprises a copolymer of a specified reactive ultraviolet absorbing compound and a radical-polymerizable monomer. CONSTITUTION:The title absorber is formed from an ultraviolet absorbing copolymer which has a weight-average molecular weight of 1,000 to 100,000 as determined by GPC and comprises a copolymer of a reactive ultraviolet absorbing compound having a radical-reactive double bond (e.g. a compound of the formula) and a radical-polymerizable monomer having polyfluoroalkyl or polyfluoroether groups (e.g. a perfluoroalkylethyl acrylate) at a molar ratio of (90:10) to (10:90).

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ultraviolet absorbers.

0002

[Prior Art] Fluororesins include polytetrafluoroethylene, tetrafluoroethylene-perfluorovinylether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, etc. It is widely used as a moldable material with excellent heat resistance, chemical resistance, and electrical properties. It also has excellent weather resistance and is effective as a protective coating material for various articles.

However, since the fluororesin itself has almost no ability to absorb ultraviolet rays, when the resin is used as a weather-resistant protective coating, it is essential to add an ultraviolet absorber or an ultraviolet shielding agent. However, the minimum moldable temperature of this resin is 280 to 300°C or higher, whereas the boiling point or volatilization start temperature of ordinary ultraviolet absorbers is
Since the temperature was 150 to 250°C, a large amount of the ultraviolet absorber mixed during hot molding volatilized, making it impossible to exhibit sufficient ultraviolet absorbing ability. Further, even if some amount of ultraviolet absorber is contained in the resin, it has poor compatibility with the resin and bleeds out after long-term use, making it impossible to exhibit ultraviolet absorbing ability.

[0004] Polyfluorinated vinyl resin is also
It is also known that, as shown in No. 37-11224, it is possible to produce a composition with sufficient ultraviolet absorbing ability by dissolving an ultraviolet absorber in a latent solvent and performing cast molding. . However, its use has been limited because the process is complicated and the composition has drawbacks in its chemical resistance and flame retardancy.

[0005]

[Problems to be Solved by the Invention] The present invention is an attempt to solve the problems of the prior art as described above, and it is a fluororesin that does not volatilize during heat molding and does not bleed out even during long-term use. The present invention provides an ultraviolet absorber that retains ultraviolet absorption ability.

[0006]

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and consists of a reactive ultraviolet absorbing compound having a radically reactive double bond, and a polyfluoroalkyl group or polyfluoroether. A copolymer of a radically polymerizable monomer having a group with a molar composition ratio of 90
The present invention provides an ultraviolet absorber made of an ultraviolet absorbing copolymer, which has a weight average molecular weight of 1,000 to 100,000 as measured by GPC.

[0007] As the reactive ultraviolet absorbing compound having a radically reactive double bond in the present invention, the following chemical formula 1,
Compounds having benzophenone-based, phenylsalicylate-based, or benzotriazole-based basic structures represented by chemical formulas 2 and 3 are employed.

[0008]

[Chemical formula 1]

[0009]

[Case 2]

0010

[C3]

[0011] In addition to the above-mentioned basic structure, the reactive ultraviolet absorbing compound has a radically reactive double bond. Groups having radically reactive double bonds include vinyl groups,
Examples include allyl group, acryloyl group, and methacryloyl group. An acryloyl group or a methacryloyl group is preferred from the viewpoint of copolymerizability with a radically polymerizable monomer having a polyfluoroalkyl group or a polyfluoroether group, which will be described later. Specifically, compounds shown in Chemical Formulas 4, 5, and 6 are employed.

0012

[C4]

[0013]

[C5]

[0014]

[C6]

In formulas 4, 5, and 6, R1 and R2 are each independently H, OH, alkyl, alkoxy, aryl, halogen, aralkyl, carboxylic acid, amino, or an acryloyl or methacryloyl group-containing group, At least one of R1, R2 is an acryloyl or methacryloyl group-containing group. R3 is an acryloyl or methacryloyl group-containing group. R
4 is halogen or H. R5 is H, alkyl, alkoxy, alkylsulfonyl, sulfonic acid, carboxylic acid, halogen, or an acryloyl or methacryloyl group-containing group. R6 and R8 are each independently H, alkyl, alkoxy, aralkyl, halogenaryl or cycloalkyl group. R7 is H, OH, alkoxy, alkyl, or an acryloyl or methacryloyl group-containing group.

In addition, the reactive ultraviolet absorbing compound having a radically reactive double bond in the present invention is a benzophenone type, phenyl salicylate type, or benzotriazole type having a hydroxyl group (excluding the hydroxyl group in the above basic structure) or an amino group. A method of introducing an acryloyl group or a methacryloyl group by reacting a compound with acrylic acid or methacrylic acid, or a method of introducing an acryloyl group or a methacryloyl group into a benzophenone-based, phenylsalicylate-based, or benzotriazole-based compound having a sulfonic acid group or a carboxylic acid group, vinyl alcohol, aminoalkyl acrylate, or amino acid. There is a method of reacting an alkyl methacrylate to introduce a radically reactive double bond.

In the present invention, as the radically polymerizable monomer having a polyfluoroalkyl group or a polyfluoroether group, an unsaturated ester having a polyfluoroalkyl group or a polyfluoroether group having 4 to 21 carbon atoms is preferably employed. be done.

A polyfluoroalkyl group or a polyfluoroether group having too few carbon atoms is not preferred because sufficient compatibility with the fluororesin etc. may not be obtained. Further, those having a large number of carbon atoms are undesirable because of their high polymerizability.

Specific examples of the radically polymerizable monomer having a polyfluoroalkyl group or a polyfluoroether group include the compounds listed in Chemical Formula 7.
Acrylate or methacrylate is preferably employed from the viewpoint of copolymerizability with the above-mentioned reactive ultraviolet absorbing compound having a radically reactive double bond.

[0020]

[Chemical 7]CH2=C(CH3)COOCH2(CF2)
4CF3CH2=C(CH3)COOCH2CH2(C
F2)6CF3CH2=CHCOO(CF2)6CF3
CH2=CHCOOCH2CH2(CF2)7CF3C
H2=CHCOOCH2CH2(CF2)5CF(CF
3) 2CH2=C(CH3)COOCH(OCOCH3
)CH2(CF2)6CF(CF3)2CH2=CHC
OOCH2CH(OH)CH2(CF2)6CF(CF
3) 2CH2=CHCOOCH2CH2(CF2)8C
F3CH2=C(CH3)COOCH2CH2NHCO
(CF2)8CF3CH2=CHOCONHCO(CF
2) 7CF(CF2Cl)CF3CH2=CHCOOC
H2CH2N(C3H7)SO2(CF2)7CF3C
H2=CHCOOCH2CH2CH2CH2(CF2)
7CF3CH2=C(CH3)COOCH2CH2N(
C2H5)SO2(CF2)7CF3CH2=CHCO
OCH2CH2NHCO(CF2)7CF3CH2=C
HCOO(CH2)3(CF2)6CF(CF3)2C
H2=CHCOOCH2(CF2)10HCH2=C(
CH3)COOCH2(CF2)10CF2ClCH2
=CHCONHCH2CH2OCOCF(CF3)OC
3F7CH2=CHCONHCH2CH2OCOCF(
CF3)(OC3F6)2OC3F7

Copolymerization of a reactive ultraviolet absorbing compound having a radically reactive double bond and a radically polymerizable monomer having a polyfluoroalkyl group or a polyfluoroether group can be carried out by a conventional method, for example, as described in Japanese Patent Publication No. 1983- This can be carried out by methods such as those described in Japanese Patent Application Laid-open No. 47716 and Japanese Patent Application Laid-Open No. 118882/1982.

[0022] The reactive ultraviolet absorbing compound having a radically reactive double bond and the radically polymerizable monomer having a polyfluoroalkyl group or polyfluoroether group may be used alone or in combination of two or more. They may be copolymerized, but if the molar ratio in each copolymer is 9
The ratio should be between 0:10 and 10:90. If this ratio is out of range, compatibility with the fluororesin and ultraviolet absorption performance will not be compatible, which is not preferable.

[0023] Furthermore, the copolymerization ratio of the above two types of compounds is 5
Other monomers may be copolymerized within a range of 0 mol% or more. Examples of such monomers include alkyl acrylates, alkyl methacrylates, and functional group-containing monomers such as hydroxyalkyl acrylates, glycidyl methacrylates, aminoalkyl acrylates, and methacrylic acid.

[0024] Furthermore, the ultraviolet absorbing product in the present invention is
Weight average molecular weight measured by PC is 1000-10
It is 0000. If the weight average molecular weight is too small, it is undesirable because it may volatilize when mixed with the fluororesin. Also, if the size is too large, it becomes difficult to mix uniformly, so it is not preferable.

The ultraviolet absorbent of the present invention can be added to various resins by a conventional method of adding additives to resins. For example, there is a method in which an appropriate amount of an ultraviolet absorber is added to a resin and the mixture is melt-kneaded.

Furthermore, since the ultraviolet absorber of the present invention has a basic structure of a polyfluoroalkyl group or a polyfluoroether group and ultraviolet absorbency, additives or treatments that simultaneously achieve water and oil repellency and ultraviolet absorbency may be added. It can be used as an agent. When used as a processing agent, it is preferable to dissolve or disperse it in an appropriate solvent.

Furthermore, since the ultraviolet absorber of the present invention has a polyfluoroalkyl group or a polyfluoroether group, it is predicted that when added to a paint, it will be oriented near the surface of the paint film. It can be expected to have an ultraviolet absorption effect. Therefore, it is useful as an additive for pigmented paints and transparent topcoats.

[0028]

[Example] The following is a concrete explanation using examples.
The present invention is not limited in any way by these examples.

Example 1 Synthesis of copolymer of 2-(3'-hydroxy-4'-benzyl)-phenoxyethyl methacrylate and perfluoroalkylethyl acrylate 100 parts of acetone and chemical formula 8 were placed in an autoclave equipped with a stirrer.
2-(3'-hydroxy-4'-benzyl)-phenoxyethyl methacrylate (hereinafter referred to as T-1) shown in
7) 71 parts perfluoroalkylethyl acrylate (hereinafter abbreviated as FA) (
The number of carbon atoms in the perfluoroalkyl group is 6 to 14, and the molar ratio is 6:8:10:12:14
mixture = 1:59:30:8:2) 126 parts,
Add 0.1 part of peroxybutyl isobutyrate,
The inside of the autoclave was purged with nitrogen, and the inside of the autoclave was heated to 65° C. while stirring, and after maintaining the temperature for 5 hours, it was cooled and the polymer solution was taken out.

The resulting polymer solution was mixed with 20 times the amount of methanol to precipitate the polymer, filtered through a glass filter, and dried at 150° C. for 8 hours to obtain a polymer. The conversion was 81% based on the amount of monomer charged and the amount of polymer obtained. DMF was used as a solvent
The weight average molecular weight was approximately 5000 as determined by GPC. Fluorine content analysis revealed that the molar ratio of T-17/FA in the copolymer was 76.6/23.4.

[0031]

[Chemical formula 8]

Comparative Example 1 Synthesis of 2-(3'-hydroxy-4'-benzyl)-phenoxyethyl methacrylate polymer 142 parts of T-17 was charged instead of 71 parts of T-17 and 126 parts of FA in Example 1. Except for this, 111 parts of T-17 homopolymer was synthesized using the same polymerization method and post-treatment method as in Example 1. DMF was used as a solvent
The weight average molecular weight was approximately 5,500 by GPC measurement.

Test Example The molar ratios of tetrafluoroethylene, chlorotrifluoroethylene, and ethylene were 45, 24, and 31,
The volumetric flow rate at 300 °C is 90 mm3/sec,
Melting point: 201℃, thermal decomposition point: 367℃, oxygen index: 76
To 100 parts by weight of the fluororesin, the copolymer obtained in Example 1, the polymer obtained in Comparative Example 1, or 2-hydroxy-4-n-octoxybenzophenone (indicated simply as UVA in Table 1) Add and mix 5 parts by weight of
A 25 μm film was prepared by extrusion molding at ℃. Table 1 shows the results of evaluating the compatibility of the ultraviolet absorber, processability, ultraviolet transmittance, and ultraviolet transmittance after 1000 hours on a Sunshine Weather-Ometer for this film.

[0034]

[Table 1]

[0035]

Effects of the Invention The ultraviolet absorber of the present invention is effective as an additive for fluororesins, and sufficient ultraviolet absorbing performance can be achieved by adding a small amount. Moreover, its performance does not deteriorate over a long period of time. Additionally, it is useful as a paint additive.

Claims (3)

[Claims] Claim 1: A copolymer of a reactive ultraviolet absorbing compound having a radically reactive double bond and a radically polymerizable monomer having a polyfluoroalkyl group or a polyfluoroether group, the molar composition ratio of which is 90. vs. 10 to 10 vs. 9
0, and the weight average molecular weight measured by GPC is in the range of 1,000 to 100,000. 2. The ultraviolet absorber according to claim 1, wherein the reactive ultraviolet absorbing compound having a radically reactive double bond is a benzophenone, phenylsalicylate or benzotriazole compound having an acryloyl or methacryloyl group. [Claim 3] The radically polymerizable monomer having a polyfluoroalkyl group or a polyfluoroether group has a carbon number of
The ultraviolet absorber according to claim 1, which is an acrylate or methacrylate having 4 to 21 polyfluoroalkyl groups or polyfluoroether groups.