JPH0591937A - Plastic mirror - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a plastic mirror excellent in heat resistance, shape stability and mechanical strength. [Constitution] The N-alkyl-substituted maleimide component is a polymer
30 to 98 mol% of the whole, olefin component is 70 to 2 mol% of the whole polymer, and vacuum deposition is performed on one surface of a synthetic resin plate having a polystyrene-equivalent weight average molecular weight of 1 × 10 ³ or more and 5 × 10 ⁶ or less. A plastic mirror characterized by having a reflective film formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic mirror which uses an N-alkyl-substituted maleimide-olefin copolymer and is excellent in heat resistance, shape stability and mechanical properties.

[0002]

2. Description of the Related Art Conventionally, a plastic mirror in which a vacuum deposition film such as aluminum is formed on a methacrylic resin is lightweight,
It is widely used in terms of workability and impact resistance. However, the heat resistance is as low as about 100 ° C., so that the range of use is limited. Further, there is a problem in shape stability due to thermal expansion.

[0003]

An object of the present invention is to provide a plastic mirror excellent in heat resistance, shape stability, mechanical strength and the like.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of this problem, the present inventor has found that N-alkyl-substituted maleimide-
A plastic mirror characterized in that a vacuum-deposited reflective film is formed on a synthetic resin plate made of an olefin-based copolymer.
However, they have found that the above problems can be solved, and have completed the present invention.

That is, in the present invention, the component (I) shown below is 30 to 98 mol% of the whole polymer and the component (II) is 2 to 70 mol% of the whole polymer, and the weight in terms of polystyrene is used. Average molecular weight is 1 × 10 ³ or more 5 × 1
0 ⁶ excellent heat resistance, characterized in that the formation of the vacuum deposited reflective film on one side of the less is a synthetic resin plate, the shape stability and plastic mirror having a mechanical strength - about.

[0006]

[Chemical 3] (Here, R ₁ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms)

[0007]

[Chemical 4] (Here, R ₂ is hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ₃ and R ₄ represent an alkyl group having 1 to 8 carbon atoms.) The resin described above is, for example, an N-alkyl-substituted maleimide. It can be obtained by a radical copolymerization reaction of olefin with olefins.

The compound which gives the component (I) is N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, Ni-propylmaleimide, Nn.
-Butyl maleimide, N-i-butyl maleimide, N-
s-Butyl maleimide, Nt-butyl maleimide, N
-N-pentyl maleimide, N-n-hexyl maleimide, N-n-heptyl maleimide, N-n-octyl maleimide, N-lauryl maleimide, N-stearyl maleimide, N-cyclopropyl maleimide, N-cyclobutyl maleimide, N N-alkyl-substituted maleimides such as -cyclohexylmaleimide, with methylmaleimide, ethylmaleimide, isopropylmaleimide and cyclohexylmaleimide being preferred. These can be used alone or in combination of two or more.

The compounds which give the component (II) are isobutene, 2-methyl-1-butene, 2-methyl-1-pentene, 2-methyl-1-hexene and 1-methyl-1-.
With olefins such as heptene, 1-isooctene, 2-methyl-1-octene, 2-ethyl-1-pentene, 2-methyl-2-butene, 2-methyl-2-pentene, 2-methyl-2-hexene Yes, isobutene is preferred.
These can be used alone or in combination of two or more.

The content of the constituent component (I) is 30 to 98 mol%, 40 to 75 mol%, especially 5% of the whole polymer.
0 to 70 mol% is preferable. When the constituent component (I) exceeds 98 mol%, the polymer produced becomes brittle, which is not preferable. On the other hand, if it is less than 30 mol%, the heat resistance of the polymer decreases, which is not preferable.

If necessary, other vinyl monomers can be copolymerized within the range not impairing the object of the present invention. Other vinyl monomers include styrene and α
-Methylstyrene, vinyltoluene, 1,3-butadiene, isoprene and halogen-substituted derivatives thereof,
Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, etc. Acrylic acid esters, vinyl acetate, vinyl benzoate and other vinyl esters, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether,
Vinyl ethers such as butyl vinyl ether, vinyl chloride, vinylidene chloride, maleic anhydride, N-phenylmaleimide, N-carboxyphenylmaleimide, acrylonitrile, ethylene, propylene, 1-butene, 2-
One or more compounds selected from butene and 1-hexene can be mentioned.

For the polymerization of these monomers, any of known polymerization methods such as bulk polymerization method, solution polymerization method, suspension polymerization method and emulsion polymerization method can be adopted.

Examples of the polymerization initiator include benzoylperoxide, laurylperoxide, octanoylperoxide, acetylperoxide, di-t-butylperoxide, t-butylcumylperoxide, dicumylperoxide, t-butylperoxyacetate.
, An organic peroxide such as t-butylperoxybenzoate, or 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-butyronitrile), 2,2 ′ -Azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, 1,1'-
Azo-based initiators such as azobis (cyclohexane-1-carbonitrile) may be mentioned.

Solvents usable in the solution polymerization method include benzene, toluene, xylene, ethylbenzene,
Cyclohexane, dioxane, tetrahydrofuran, acetone, methyl ethyl ketone, dimethylformamide,
Examples include isopropyl alcohol and butyl alcohol.

The polymerization temperature can be appropriately set depending on the decomposition temperature of the initiator, but it is generally preferably carried out in the range of 40 to 150 ° C.

The above resin can also be obtained by post-imidizing a resin obtained by copolymerization of maleic anhydride and olefins with an alkylamine or the like.

Such post-imidization reaction is carried out, for example, by using a maleic anhydride-isobutene copolymer as an alcohol solvent such as methanol, ethanol, propanol or an aromatic solvent such as benzene or toluene. Dissolve or disperse in a group solvent etc. and add 100 with primary amine such as methylamine
It is carried out by reacting at a temperature of ˜350 ° C.

Here, the weight average molecular weight (Mw) of the resin produced is determined by gel permeation chromatography.
(GPC). The molecular weight of the resin used in the present invention is preferably 1 × 10 ³ or more and 5 × 10 ⁶ or less, and particularly preferably 1 × 10 ⁵ or more and 1 × 10 ⁶ or less.
If the molecular weight exceeds 5 × 10 ⁶ , moldability tends to be poor, and if it is less than 1 × 10 ³ , the resin obtained tends to become brittle.

The resin obtained in the present invention may optionally contain various dyes, inorganic and organic particles, hindered phenols, heat stabilizers such as organic phosphates, benzotriazole type or hindered amines. An ultraviolet stabilizer such as a system, a flame retardant, an antistatic agent, various lubricants and the like may be added.

It is also possible to mix other resins, rubbers and the like. Further, the above polymerization is carried out in the presence of a rubber-like polymer,
It is also possible to use a graft polymer.

The plastic mirror of the present invention can be obtained by vapor-depositing a metal such as aluminum or copper by a known vacuum vapor deposition method using a plate made of the above resin.

The plastic mirror of the present invention can be treated with a hard coating, an antireflection film or the like. Furthermore, 2
A double-sided mirror can be obtained by laminating the sheets or forming a transparent protective coating film on the vacuum vapor deposition reflection film.

[0023]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples.

The molecular weight of the produced polymer is GPC (Tohso
It was determined by polystyrene conversion using HLC-802A manufactured by Co., Ltd.

Example 1 50 equipped with a stirrer, nitrogen inlet tube, thermometer and degassing tube
1980 g of N-methylmaleimide 2780 g
(25 mol), 2,2'-azobisisobutyronitrile (AIBN) 3.2 g (0.02 mol) and dioxane 40 l were charged, and after purging with nitrogen several times, isobutene 2805 g (50 mol). Was charged and reacted at 60 ° C. for 12 hours.

The reaction contents were poured into ethanol and polymerized.
Was deposited. The obtained polymer was purified by reprecipitation with dioxane-methanol, and then dried under reduced pressure at 60 ° C. for 24 hours. The yield was 4030 g.

Elemental analysis results of the obtained polymer (C; 6
4.7 wt%, H; 7.8 wt%, N; 8.4 wt%)
Therefore, the maleimide unit in the produced polymer was 50 mol%. The obtained polymer has a molecular weight (Mw) of 22,300.
It was 0.

The resin obtained is extruded to a thickness of 3 m.
m resin plate, aluminum was vapor-deposited on one surface of the resin plate to obtain a plastic mirror sample.

The flexural strength and flexural modulus of the obtained sample are ASTM D790, and the heat distortion temperature is ASTM D
648 and the coefficient of linear thermal expansion were measured according to ASTM D696, respectively. The characteristic evaluation results are shown in Table 1.

Example 2 By the same method as in Example 1 except that N-isopropylmaleimide was used instead of N-methylmaleimide.
An N-isopropylmaleimide-isobutene copolymer was synthesized.

From the result of elemental analysis of the obtained polymer, the maleimide unit in the produced polymer was 50 mol%.
The obtained polymer had a molecular weight (Mw) of 181,000.

Using the resin thus obtained, a sample was prepared in the same manner as in Example 1. The characteristic evaluation results are shown in Table 1.

Example 3 An N-cyclohexylmaleimide-isobutene copolymer was synthesized by the same method as in Example 1 except that N-cyclohexylmaleimide was used instead of N-methylmaleimide.

From the results of elemental analysis of the obtained polymer, the maleimide unit in the produced polymer was 51 mol%.
The obtained polymer had a molecular weight (Mw) of 172,000.

Using the resin thus obtained, a sample was prepared in the same manner as in Example 1. The characteristic evaluation results are shown in Table 1.

Comparative Example 1 For comparison, a sample was prepared in the same manner as in Example 1 using Acrypet (acrylic resin, manufactured by Mitsubishi Rayon). The characteristic evaluation results are shown in Table 1.

[0037]

[0038]

As is apparent from the examples, the plastic mirror of the present invention has a high thermal deformation temperature and a small coefficient of linear thermal expansion, and thus is very stable to heat. In addition, since it has good mechanical properties, it is extremely useful in practice.

Claims (1)

[Claims] 1. The component (I) shown below is 30 to 98 mol% of the whole polymer, the component (II) is 70 to 2 mol% of the whole polymer, and the weight average molecular weight in terms of polystyrene is 1. A plastic mirror, characterized in that a vacuum evaporation reflective film is formed on one surface of a synthetic resin plate having a size of 10 ^{3 to} 5 10 ⁶ . [Chemical 1] (Here, R ₁ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms) (Here, R ₂ is hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ₃ and R ₄ are alkyl groups having 1 to 8 carbon atoms)