JPH0651783A - Sound insulating plate for road - Google Patents

Abstract

PURPOSE:To provide the sound insulating plate for roads which is highly resistant to staining, is easily removable and maintains the initial transparency and appearance without impairment by specifying the mol. wt. of a polycarbonate resin. CONSTITUTION:The polycarbonate resin having 40000 to 100000 weight average mol. wt. is used as a basic blank material. A remarkable improvement in exhaust gas resistance is admitted with the polycarbonate resin sheet having <=40000 weight average mol. wt. The exhaust gas resistance is better as the weight average mol. wt. is higher, but the moldability is poorer as the weight average mol. wt. is higher in the case of molding to a sheet shape and, therefore, the resin sheet having substantially <=150000 weight average mol. wt. is used. The range of the weight average mol. wt. of the polycarbonate resin preferable as the sound insulating board for roads is 40000 to 100000, more preferably 45000 to 80000 when both the exhaust gas resistance and moldability are considered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road sound insulating board having a light transmitting property. Particularly, the present invention relates to a road sound insulation plate that is not easily soiled.

[0002]

2. Description of the Related Art Polycarbonate resin sheets can be used as a sound insulating plate material for road sound insulating plates, especially for highways, etc., which has good sound insulating properties, and also has excellent transparency and translucency and is aesthetically pleasing. Is already known.
This is because not only the polycarbonate resin sheet is excellent in transparency, but also the impact resistance is excellent and the on-site workability is good. However, the sound-insulating plate made of a polycarbonate resin sheet that has been used up to now has a problem that the surface is easily soiled, the light-transmitting property / transparency is deteriorated by long-term use, and the aesthetic appearance is deteriorated. In order to solve this problem, for example, a troublesome and expensive work such as periodical washing with water or washing with a detergent is required. Remained difficult to remove, and there was still the problem of blackening and increasing opacity.

[0003]

DISCLOSURE OF THE INVENTION The present invention has improved the above-mentioned drawbacks of the road sound insulation board made of a polycarbonate resin sheet which has been used so far, and is hard to be soiled. It is an object of the present invention to provide a road sound insulation plate that can be easily removed and is less likely to impair transparency and aesthetics.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have found that conventional polycarbonate resin sheets used as road sound insulation plates are easily contaminated by exhaust gas components of automobiles, trucks, buses, etc., especially aromatic carbonization. It was found that the chemical resistance to hydrogen is not good, and therefore the surface of the sheet is invaded by the exhaust gas component to cause fine cracks or fine irregularities, resulting in loss of surface smoothness. They also found that dirt floating in the vicinity of the road and soot in exhaust gas adhere to the surface of the roughened sheet, so that dirt becomes noticeable. It was also found that dust and soot that entered and adhered to the fine recesses formed on the surface of the sheet could not be easily removed even by washing.

Therefore, the inventors of the present invention have conducted extensive studies on a polycarbonate resin sheet having resistance to exhaust gas of automobiles, and as a result, found that the resistance to exhaust gas changes depending on the molecular weight of the polycarbonate resin, and the present invention is realized. It came to completion. That is, the present invention is
Weight average molecular weight (Mw) is 40,000 to 100,000
Provided is a sound insulation plate for roads, which uses a polycarbonate resin sheet of 0 as a basic material.

The weight average molecular weight of the sheet-shaped polycarbonate resin used so far as a sound insulation plate for roads is
It was found that the polycarbonate resin sheet having a weight average molecular weight of at most 35,000 and having a weight average molecular weight of less than 35,000 was not good in exhaust gas resistance, but the weight average molecular weight was 40,0.
It has now been found that a polycarbonate resin sheet of 00 or more has dramatically improved exhaust gas resistance. It was found that the higher the weight average molecular weight is, the better the exhaust gas resistance is, but when the polycarbonate resin is molded into a sheet, the moldability becomes worse as the molecular weight increases. Molecular weight is 150,000
Those of 0 or less are used. From the viewpoint of both exhaust gas resistance and moldability, the range of the weight average molecular weight of the polycarbonate resin sheet which is preferable as the road sound insulation plate is 40,000.
0 to 100,000, more preferably 45,000
It is in the range of 0 to 80,000.

The polycarbonate resin sheet in the molecular weight range used in the present invention or the resin as a raw material thereof has a higher molecular weight than that which is usually commercially available. Such high molecular weight polycarbonate may be produced by a known method, for example, a phosgene method or a melting method, but in any case, it is difficult to produce industrially, and a high quality polycarbonate is obtained. Is difficult to obtain. For example,
In the case of the phosgene method, the polymerization reaction must be carried out under high dilution using a large amount of chlorine-based solvent such as methylene chloride, and the polymerization solvent and by-product sodium chloride are separated from the polymer. Since it is very difficult to obtain, only low-quality products containing a large amount of chlorine-based impurities and sodium compounds have been obtained. In the polycarbonate resin sheet containing such chlorine-based impurities,
Although heat resistance and weather resistance are inferior and not preferable, any polymer having a molecular weight within the range required for the present invention can be used as the road sound insulation plate of the present invention.

Further, in the case of the melting method, since the polymerization reaction proceeds and the melt viscosity of the polycarbonate increases extremely as the molecular weight increases, it is necessary to carry out the reaction at a high temperature and a high vacuum for a long time. Therefore, it has a drawback that only a colored polymer can be obtained, and substantially, although it is difficult to obtain a high molecular weight polycarbonate necessary for the present invention, if the molecular weight can be increased, Those manufactured by the method can also be used.

As described above, it is difficult to obtain the high molecular weight polycarbonate required for the present invention by the existing method, but
The solid-phase polymerization method previously proposed by the present inventors (Japanese Patent Application Laid-Open No. 1-15
8033, JP-A 1-271426, and JP-A 3-686
No. 27, etc.), high-quality, high-molecular-weight polycarbonate can be easily obtained, and by using this resin,
A high molecular weight polycarbonate sheet can be easily obtained by the method described in JP-A-4-28716. The polycarbonate sheet used in the present invention is composed of a polycarbonate having a main chain composed of repeating units represented by the following chemical formula 1.

[0010]

[Chemical 1] In the formula, Ar is a divalent aromatic residue, and examples thereof include phenylene, naphthylene, biphenylene, pyridylene, and those represented by the following chemical formula 2.

[0011]

Embedded image wherein —Ar ¹ —Y—Ar ² — [wherein, Ar ¹ and Ar ² are each an arylene group, for example, a group such as phenylene, naphthylene, biphenylene, or pyridylene, and Y is Represents an alkylene group or a substituted alkylene group represented by 3. ]

[0012]

[Chemical 3]

(Wherein R ¹ , R ² , R ³ and R ⁴ are each a hydrogen atom, a lower alkyl group, a cycloalkyl group,
An aryl group or an aralkyl group, which may be optionally substituted with a halogen atom or an alkoxy group, and k is 3
Is an integer from ~ 11,

[Chemical 4] The hydrogen atom of may be substituted with a lower alkyl group, an aryl group, halogen or the like. )

Further, a divalent aromatic residue represented by the following chemical formula 5 may be contained as a copolymer component.

[0015]

Embedded image wherein —Ar ¹ —Z—Ar ² — [wherein Ar ¹ and Ar ² are the same as defined above, Z is a mere bond, or —O—, —CO—, —S—, —SO _{2
-, - CO 2 -, -} CON (R 1) (R 2) -,
(R ¹ and R ² are the same as above) and the like. ]

Examples of these divalent aromatic residues include those represented by the following chemical formulas 6, 7, and 8.

[0017]

[Chemical 6]

[0018]

[Chemical 7]

[0019]

[Chemical 8]

[Wherein R ⁵ and R ⁶ represent hydrogen, halogen, a C ₁ -C ₁₀ alkyl group, a C ₁ -C ₁₀ alkoxy group, a C ₅ -C ₁₀ cycloalkyl group or a phenyl group, respectively, and m And n are integers of 1 to 4, each R ⁵ may be the same or different when m is 2 to 4, and each R ⁶ may be the same when n is 2 to 4. It may be different. Among them, the one represented by the following chemical formula 9 is a preferable example.

[0021]

[Chemical 9] Particularly, those containing 85 mol% or more of the repeating unit in which the chemical formula 9 is Ar are preferable.

The polycarbonate of the present invention may contain a trivalent or higher valent aromatic residue as a copolymerization component. The molecular structure of the polymer terminal is not particularly limited, but one or more terminal groups selected from a hydroxyl group, an aryl carbonate group and an alkyl carbonate group can be bonded.

The end of the aryl carbonate group is represented by the following chemical formula 1.
0

[Chemical 10] [In the formula, Ar ³ represents a monovalent aromatic residue, and the aromatic ring is
It may be substituted. ], As a specific example,
For example,

[0024]

[Chemical 11] Etc.

The end of the alkyl carbonate group is represented by the following chemical formula 1.
Two

[Chemical 12]

[In the formula, R ⁷ represents a linear or branched alkyl group having 1 to 20 carbon atoms. ], As a specific example, for example,

[Chemical 13] Etc. Of these, a phenyl carbonate group, a pt-butylphenyl carbonate group, a p-cumylphenyl carbonate group and the like are preferably used. The hydroxyl group terminal lowers the heat resistance and the hot water resistance, and therefore it is preferably as small as possible.

The polycarbonate sheet used in the present invention may contain a commonly used additive such as a heat stabilizer, a release agent, a colorant, and a weather resistance improver. As such a heat stabilizer, for example, phosphorus-based stabilizers described in JP-A-3-163160 and JP-A-3-163161 are particularly preferably used.

As the weather resistance improver, for example, 2
-Hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2,2'-
Dihydroxy-4-methoxybenzophenone, 2,2 '
-Benzophenone-based compounds such as dihydroxy-4,4'-dimethoxybenzophenone, 2- (2'-hydroxy-5 ')
-Methylphenyl) benzotriazole, 2- (2'-
Hydroxy-3'-t-butyl-5'-methylphenyl) 5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) 5-chlorobenzotriazole, 2- (3 ′, 5′-t-amylhydroxyphenyl) benzotriazole, 2-
(2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-3 ',
5'-bis (α, α-dimethylbenzyl) phenyl)-
2H-benzotriazole, 2- (2'-hydroxy-
3 ', 5'-di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-lauryl-5'
Benzotriazoles such as -methylphenyl) benzotriazole, bis (2,2,6,6-tetramethyl-4)
-Piperidyl) sebacate and other hindered amines.

These weather resistance improvers may be used alone or in combination of two or more. Since the road sound insulation plate of the present invention is used outdoors, it needs to have high weather resistance, and particularly contains such a weather resistance improver in order to prevent yellowing due to ultraviolet rays or the like. What has been done is especially preferable.

The road soundproofing plate of the present invention is basically made of a sheet-shaped polycarbonate resin having a weight average molecular weight of 40,000 to 100,000. This basic material means that the weight average molecular weight is 40,000 to 100,000.
As long as the polycarbonate resin sheet is substantially a main material, it may be a laminate of sheets and films made of other materials for the purpose of giving other purposes and performances.

The thickness of the polycarbonate resin sheet used in the present invention is usually 1 to 15 mm, preferably 3 to 8 mm.
Is. When used as a sound insulation board for highways,
It is usually a sheet with a thickness of around 5 mm. Such a sheet is usually attached to a frame material to be used as a road sound insulation plate.

The weight average molecular weight (Mw) of the polycarbonate used in the present invention is measured by a gel permeation chromatography (GPC) method. From the calibration curve of dispersed polystyrene
It is obtained by using a reduced molecular weight calibration curve according to the formula.

[0033]

## EQU1 ## M _PC = 0.3591 M _PS ^1.0388 (M _PC represents the molecular weight of polycarbonate and M _PS represents the molecular weight of polystyrene.)

[0034]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Evaluation of acceleration of pollution: As an evaluation of acceleration of pollution of road sound insulation board, pollution by exhaust gas of diesel vehicles was evaluated.
The sheet was fixed at a distance of about 50 mm from the exhaust port of a 1800 cc diesel vehicle, and after traveling 400 km (40 km × 10 days), the sheet was removed and the appearance and light transmittance (wavelength 520 nm) were evaluated.

Examples 1,2,3 Diphenyl carbonate and 2,2-bis (4-hydroxyphenyl) propane produced by the method of JP-A-3-68627 have a weight average molecular weight of 45,000 (Example 1 ), 56,000 (Example 2), and 71,000 (Example 3) of three types of polycarbonate, and a temperature of 3
Extrusion molding was performed at 20 ° C. to obtain a sheet having a thickness of 5 mm. In order to use the sheet as a sound insulation plate for roads, a promotion evaluation of contamination was carried out, and no change in appearance was observed in all three types of sheets, and the light transmittance was 84%, which was not deteriorated at all. . FIG. 1- (a) shows that the weight average molecular weight is 56,0.
The appearance of the sheet No. 00 (Example 2) after accelerated evaluation is shown, but it is not contaminated at all.

Comparative Example 1 The same procedure as in Example 1 was carried out except that a commercially available polycarbonate (weight average molecular weight: 30,000) was used as the polycarbonate and the sheet was molded at a temperature of 300 ° C. The result of the evaluation of the pollution promotion is that the light transmittance is 85 before the evaluation of the pollution.
% To 41%, and the appearance was contaminated in black as shown in FIG. 1- (b).

[0037]

INDUSTRIAL APPLICABILITY As described above, the road sound insulation plate of the present invention has excellent resistance to pollution by exhaust gas and the like, and can be suitably used as a sound insulation plate for highways and the like. In addition, because it has excellent resistance to pollution by exhaust gas, etc.,
For example, it can be suitably used as a wainscot and a blindboard of a crossing bridge.

[Brief description of drawings]

FIG. 1 (a) shows the appearance of a polycarbonate sheet having a weight average molecular weight of 56,000 (Example 2) after evaluation of promoting stain resistance, and FIG. 1 (b) shows a polycarbonate sheet having a weight average molecular weight of 30,000 (Comparative Example 1). 2) shows the appearance after the evaluation of the promotion of contamination of ().

Claims (1)

[Claims] 1. A weight average molecular weight of 40,000 to 10
A sound insulation board for roads that uses a polycarbonate resin sheet of 10,000 as a basic material.