Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Noninterengaged fiber-containing paper-free web or sheet...
Reexamination Certificate
1998-12-04
2001-11-13
Weisberger, Richard (Department: 1774)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Noninterengaged fiber-containing paper-free web or sheet...
C428S035900, C428S113000, C428S298100, C522S004000, C522S006000, C264S257000, C264S266000, C264S279000, C264S294000, C264S478000, C264S135000, C264S136000
Reexamination Certificate
active
06316089
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a prepreg sheet for waterproofing which is used for structures in the fields of civil engineering and construction, a method for producing the prepreg sheet, and to a waterproofing method. More specifically, the present invention relates to a photocurable prepreg sheet for waterproofing that enables FRP-waterproofing to be performed in a short period of time with significantly reduced offensive smell of monomers etc. generated from photo-curing reactions by use of a photocurable prepreg sheet for waterproofing; a method for producing the prepreg sheet, an apparatus for producing the prepreg sheet continuously; and a waterproofing method using the prepreg sheet.
BACKGROUND OF THE INVENTION
Properties required of a waterproofing material used as a coating material for waterproofing the surface of concrete, mortar, or the like used in constructions such as roofs, verandas, parking lots, corridors, and swimming pools include resistance against vibrations of buildings and impact caused by fallen objects, capability of sealing the surface of a crack formed in the concrete or mortar beneath the coat, alkali-resistance, and high adhesion to the substrate.
Conventionally, asphalt and urethane resins have been used as waterproof lining materials for concrete and mortar but have been unsatisfactory. Recently, there has often been employed the FRP method, in which unsaturated polyester resin or vinyl ester resin which are endowed with pliability is combined with a fibrous reinforcing material.
Thermosetting resins used in the FRP method have been studied energetically in recent years, and there have been proposed various types of thermosetting resins such as those which are endowed with both flexibility and chemical resistance, those which exhibit a large % elongation at low temperature, and those which are endowed with air drying property, as described in Japanese Patent Application Laid-Open (kokai) Nos. 8-319328, 1-201362, 8-311805, 5-295862, 1-96079, 4-253717, and 4-142323.
When lining is performed by use of unsaturated polyester resin or vinyl ester resin, room temperature setting by use of a peroxide serving as a catalyst is normally employed. However, the room temperature setting has a drawback that it requires a step for impregnating a fibrous reinforcing material layer with a resin. Also, a long period of time is required before the resin is completely set, which leads to both decrease in working efficiency and volatilization of reactive monomers such as styrene monomers, resulting in a deteriorated resin performance due to a change in the ratio of the resin compositions, loss of resin in amount, and air pollution at the work site. Moreover, there are required intricate procedures such as measuring a peroxide serving as a catalyst with a dropping pipet and mixing it with resin at the working site. In addition, since gelation time of resin itself varies significantly with temperature, adjustment of the amount of a catalyst to be used is difficult, and failure in adjustment leads to unsuccessful adjustment of pot life of the resin.
As one means to solve these drawbacks, volatile monomers, such as styrene, contained in the resin are replaced by high-boiling-point compounds, to thereby manage the problems of air pollution and odor in the workplace. However, there remain unsolved such drawbacks involved in the system in which a peroxide catalyst is used in combination with an ambient-temperature-setting resin as in the case of unsaturated polyester resin or vinyl ester resin, which requires a long period of time for the resin to be set. Also remaining are problems that use of a peroxide as a catalyst might be hazardous, that complicated procedures are required for the addition of the peroxide as a catalyst, and that the adjustment of pot life of the resin is difficult.
There may be suggested use of a prepreg sheet that has been obtained by B-staging (prepregnating) glass fiber or similar material impregnated with an unsaturated polyester resin or a vinyl ester resin so as to achieve a hardness that allows easy handling. In this connection, room temperature setting type prepreg sheets is not usable because they can be stored for only a short period. With regard to photocurable prepreg sheets, conventional methods for prepregnating thermosetting resins—or example, metal thickening of unsaturated polyester resin by use of magnesium oxide and isocyanate thickening of vinyl ester resin—are unable to keep photocurable stable prepreg sheets. In addition, there are drawbacks that, since a reactive diluent such as a styrene monomar contained in the resin does not participate in the thickening reaction of vinyl ester resin or that of unsaturated polyester resin, resin volatilizes or escapes from the fibrous substrate during storage of the prepreg sheet.
In a conventional wet FRP-waterproofing method, a buffer layer comprised of a soft resin alone is often formed beneath the FRP lining layer so that the lining layer can seal the surface of a crack formed in the concrete. However, conventional metal thickening by use of magnesium oxide and isocyanate thickening require a long time before completion of reaction, with the result that the buffer layer and the fiber-reinforced layer are intermixed, leading to difficulty in forming a definite buffer layer. Thus, manufacture of photocurable prepreg sheets applicable to an FRP lining layer having a buffer layer thereon has been difficult.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of the present invention is to provide a waterproofing material which does not require a process of impregnating a fibrous reinforcing material with a resin at the work site, which permits installation work and setting of resin to be completed within a short period of time, and which solves drawbacks such as the risk of explosion involved in direct handling of a peroxide catalyst, intricate procedures required for the addition of the peroxide catalyst, and difficulty in the adjustment of pot life of the resin. Other objects of the present invention include provision of a manufacturing method of the waterproofing material; a waterproof-coating method, making use of the waterproofing material; a photocurable prepreg sheet which serves as a waterproofing material and which is used for an FRP lining layer having a buffer layer; a method for manufacturing the prepreg sheet; and waterproof-coating method making use of the prepreg sheet.
Accordingly, the present invention provides a photocurable prepreg sheet, a method or process for producing a photocurable prepreg sheet, an apparatus usable for producing a photocurable prepreg sheet, and a waterproofing method using a photocurable prepreg sheet as described below.
[1] photocurable prepreg sheet for waterproofing comprising:
(1) a fiber-reinforced resin layer which comprises a sheet-shaped inorganic or organic fibrous reinforcing material impregnated with a resin composition comprising:
(A) an unsaturated polyester resin and/or vinyl ester resin:
100 parts by weight, and
(B) at least two photopolymerization initiators having photosensitivity in different wavelength ranges from ultraviolet range to near infrared range:
0.01 to 10 parts by weight,
and which is treated with light of a specific wavelength to thereby undergo prepolymerization which causes at least one of the photopolymerization initiators and radical-polymerizable unsaturated groups to remain partially intact; and
(2) film which covers an upper surface and a back surface of the fiber-reinforced resin layer.
[2] A photocurable prepreg sheet for waterproofing according to [1], wherein one of the photopolymerization initiators having photosensitivity from ultraviolet range to near infrared range comprises a combination of a cationic dye and a sensitizer; the cationic dye having photosensitivity from visible light range to near infrared range and being represented by formula (1):
D
+
•A
−
(1)
wherein D
+
represents a dye cation having pho
Kadota Toshihiko
Kamata Hirotoshi
Ohtani Kazuo
Sendai Hidetake
Sugita Shuichi
Showa Denko K.K.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Weisberger Richard
LandOfFree
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