Plastic and nonmetallic article shaping or treating: processes – Forming continuous or indefinite length work – Shaping by extrusion
Reexamination Certificate
2001-09-04
2004-05-25
Woodward, Ana (Department: 1711)
Plastic and nonmetallic article shaping or treating: processes
Forming continuous or indefinite length work
Shaping by extrusion
C428S220000, C524S100000, C524S538000
Reexamination Certificate
active
06740275
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a flame-retardant polyamide-based protective sheet, and more particularly, to a protective sheet containing a halogen-free flame retardant which is excellent in flame retardancy, incineration property, environmental suitability, flexibility, tear property, heat resistance, heat-aging resistance, mechanical strength, workability and industrial productivity.
Conventional protective sheets have been usually produced from polyolefins such as EVA. It has now been required to impart a good flame retardancy to these protective sheets for the purpose of improving a safeness thereof when used for covering buildings such as domiciles, ware houses, tents and electric power plants, automobiles, or the like. Hitherto, vinyl chloride sheets have been extensively used as flame-retardant protective sheets because of excellent flame retardancy and tenacity thereof. However, in recent years, there is such a social demand that the use of halogen-based compounds which tend to cause environmental pollution and damage to human health, should be avoided. From this viewpoint, the vinyl chloride sheets are unsuitable as protective sheets.
On the other hand, since polyolefins themselves are poor in flame retardancy, it is difficult to impart a flame retardancy thereto without incorporating halogens thereinto. Even If the polyolefins successfully show a flame retardancy without using halogens, polyolefin-based sheets still tend to suffer from electrostatic firing or shock due to easy electrification thereof unless they are subjected specific antistatic treatments, and have problems such as poor workability due to high specific gravity thereof, and very poor mechanical strength and productivity. In addition, the polyolefin-based sheets containing metals, etc. have further problems such as generation of corrosive or harmful gases as well as poor workability, low safety and deteriorated maintenance of incineration facilities due to residual ashes upon incineration thereof.
Thus, conventional protective sheets have failed to show excellent flame retardancy, incineration property, environmental suitability, flexibility, tear property, heat resistance, heat-aging resistance, mechanical strength, workability and industrial productivity.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a protective sheet which is excellent in flame retardancy, incineration property, environmental suitability, flexibility, tear property, heat resistance, heat-aging resistance, mechanical strength, workability and industrial productivity.
To attain the above aim, in the first aspect of the present invention, there is provided a flame-retardant polyamide-based protective sheet comprising a polyamide resin composition comprising 98 to 70 parts by weight of a polyamide resin and 2 to 30 parts by weight of a triazine-based flame retardant, and produced by extrusion-molding said polyamide resin composition.
In a second aspect of the present invention, there is provided an extrusion-molded flame-retardant polyamide-based protective sheet which comprises:
a layer A comprising a polyamide resin composition comprising 98 to 70 parts by weight of a polyamide resin and 2 to 30 parts by weight of a triazine-based flame retardant, and
a layer B which comprises at least one thermoplastic resin and is laminated on at least one surface of said layer A;
the ratio of a thickness of said layer B to a thickness of said layer A being less than 0.8.
In a third aspect of the present invention, there is provided an extrusion-molded laminated sheet which comprises:
a layer A comprising a polyamide resin composition comprising 98 to 70 parts by weight of a polyamide resin and 2 to 30 parts by weight of a triazine-based flame retardant; and
a layer B which comprises at least one thermoplastic resin and is laminated on at least one surface of said layer A;
the ratio of a thickness of said layer B to a thickness of said layer A being less than 0.8.
In a fourth aspect of the present invention, there is provided a flame-retardant polyamide-based protective sheet which comprises a polyamide resin composition comprising 99 to 40 parts by weight of a polyamide resin, 1 to 40 parts by weight of a triazine-based flame retardant, and 0.1 to 20 parts by weight of an ester compound obtained by esterifying p-hydroxybenzoic acid, o-hydroxybenzoic acid or mixture thereof, with a branched aliphatic alcohol having 12 to 22 carbon atoms; and which is produced by extrusion-molding said polyamide resin composition.
In a fifth aspect of the present invention, there is provided a polyamide resin composition comprising 99 to 40 parts by weight of a polyamide resin, 1 to 40 parts by weight of a triazine-based flame retardant, and 0.1 to 20 parts by weight of an ester compound obtained by esterifying p-hydroxybenzoic acid, o-hydroxybenzoic acid or mixture thereof, with a branched aliphatic alcohol having 12 to 22 carbon atoms.
In a sixth aspect of the present invention, there is provided an extrusion-molded flame-retardant polyamide-based protective sheet comprising:
a layer A comprising a polyamide resin composition comprising 99 to 40 parts by weight of a polyamide resin, 1 to 40 parts by weight of a triazine-based flame retardant, and 0.1 to 20 parts by weight of an ester compound obtained by esterifying p-hydroxybenzoic acid and/or o-hydroxybenzoic acid, with a branched aliphatic alcohol having 12 to 22 carbon atoms; and
a layer B laminated on at least one surface of said layer A, said layer B comprising at least one thermoplastic resin,
the ratio of a thickness of said layer B to a thickness of said layer A being less than 0.8.
In a seventh aspect of the present invention, there is provided an extrusion-molded laminated sheet comprising:
a layer A made of a polyamide resin composition comprising 99 to 40 parts by weight of a polyamide resin, 1 to 40 parts by weight of a triazine-based flame retardant, and 0.1 to 20 parts by weight of an ester compound obtained by esterifying p-hydroxybenzoic acid, o-hydroxybenzoic acid or mixture thereof, with a branched aliphatic alcohol having 12 to 22 carbon atoms; and
a layer B which comprises at least one thermoplastic resin and is laminated on at least one surface of said layer A,
the ratio of a thickness of said layer B to a thickness of said layer A being less than 0.8.
In a eighth aspect of the present invention, there is provided an extrusion-molded product produced by extrusion-molding the polyamide resin composition according to the above fifth aspect of the present invention.
In a ninth aspect of the present invention, there is provided a tube produced by extrusion-molding the polyamide resin according to the above fifth aspect of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. Meanwhile, in general definitions, “sheets” mean those having a thickness of not less than 0.254 mm ({fraction (1/100)} inch), and “films” mean those having a thickness of less than 0.254 mm. However, the sheets described herein should be construed to involve both the “sheets” and “films”.
The “protective sheet” of the present invention means those sheets used for protecting working portions upon building construction or painting. For example, the protective sheet is used to shield working sites and peripheral portions thereof in plaster works or painting works as well as finished paint surface, and avoid possible danger in construction work field.
In practical applications, the protective sheet (curing sheet) may be used, for example, (1) to enclose or surround building construction sites, construction work fields or floors for preventing dirt or dusts from being scattered outside or for eliminating the occurrence of possible dangers; (2) to enclose or surround ware houses, tents or insides thereof as well as floors for preventing rainwater from entering thereinto or for preventing these places from being contaminated; (3) to enclose or surround local working sites within electric power plants or othe
Morimoto Seiji
Nakata Michio
Tsunoda Morio
Urabe Hiroshi
Conlin David G.
Edwards & Angell LLP
Hazzard Lisa Swiszcz
Mitsubishi Engineering-Plastics Corporation
Woodward Ana
LandOfFree
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