CA1043245A

CA1043245A - Marble-patterned bathtub, basin or sink

Info

Publication number: CA1043245A
Application number: CA241,456A
Authority: CA
Inventors: Yasuharu Nakagawa
Original assignee: TOPLA Ltd
Current assignee: TOPLA Ltd
Priority date: 1975-04-26
Filing date: 1975-12-10
Publication date: 1978-11-28
Also published as: AU8744775A; GB1472150A; FR2308498A1; JPS5627259B2; IT1051532B; JPS51127861A; DE2600450C3; FR2308498B1; DE2600450A1; DE2600450B2

Abstract

ABSTRACT OF THE DISCLOSURE
A marble-patterned enclosure such as a bathtub, basin or sink is provided wherein a marble pattern is applied to the back of a transparent acrylic sheet prior to thermoforming. After the acrylic sheet with the marble pattern applied to the back thereof has been themoformed into the desired configuration, a layer of opaque-colored primer, which is a paint consisting essentially of unsatu-rated polyester and/or acrylic resin and pigment is applied on the pattern printed exterior side of the configuration for the dual purposes of preventing the marble pattern from bleeding, discoloration, etc. and to increase both impact strength and heat resistance of the formed structure.
Thereafter on top of the primer, another layer of fiber glass reinforced polyester is applied to provide general reinforcement of the structure. The enclosure of the present invention can easily and inexpensively be fabri-cated according to this procedure and possesses the appea-rance of natural marble over the entire outside of the enclosure with superior impact strength and heat resistance.

Description

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~he present invention relates to a marble-patterned enclosure such as a bathtub, basin or sink wherein the marble ~ ;
pattern is applied prior to thermoforming to one side of a transparent acrylic sheet which is then thermoformed into the desired configuration and reinforced with a layer of opaque-colored primer and a layer of glass fiber reinforced poly-ester applied over the pattern imprinted back of the acrylic sheet and having a color so as to make the marble pattern ~i appear clearly and resemble natural marble.
In recent years bathtubs and other enclosures, either made of marble or having the appearance of marble, have become increasingly popular. ~ecause, however, of the high expense of solid marble enclosures and fixtures, it has become the practice to fabricate these enclosures and fixtures from acrylic sheets. Ordinarily, these enclosures and fixtures are made of acrylic sheet produced by the continuous casting method. This procedure has the disadvantage, however, that pigments are frequently unevenly distributed within the sheet and there is the further problem that these acrylic 20 sheets, once they are formed into the fixture, tend to de- ! ' terioriate or become weakened in locali~.ed areas. Also due i` ;~
to the production techniques which are employed in fabricating enclosures and fixtures from these sheets, it is often diffi-cult to repeat or match specific patterns which may be desired) and it is not infrequent that some localized areas do not match in color or in pattern with the result that a part of the sheet is discarded and wasted. ~urther, the continuous casting method being essentially a mass production system, it is impossible to produce a small batch to suit individual requirements.
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In order to overcome the short comings, attempts have been made to apply patterns to acrylic sheets after thermoforming by spraying or applying a printed polyester or polystyrene film to the back of the formed acrylic sheet.
Spraying to produce a desired pattern has, however, the disadvantage that it requires a high degree of skill on the part of the individual doing the spraying in order to produce a desired uniform appearance. Further, such spraying techniques cannot be applied to mass producing uni~orm designs, since the appearance of each article will neces-sarily vary somewhat. The application of printed polyester or polystyrene films to thermoformed acrylic sheets has the disadvantage that it is quite difficult to apply evenly the film to -the intricate corners and undulations in the formed -, article thus resulting in a product with unsatisfactory appearance particularly at the corners and edges. `
Accordingly, it is an object of the present inven-tion to provide an inexpensive marble-patterned enclosure which is light in weight and high in rigidity and which has a marble pattern having an even appearance which can be re-produced exac~ly in any number of articles.
It is a further object of the present invention to provide a molded marble-patterned enclosure such as a -~
bathtub or basin which can easily and inexpensively be fabricated in order to have the above-noted characteristics.
According to the present invention, an enclosure or fixture such as a bathtub or basin having a marble pattern is fabricated by applying a printed marble pattern to one side of a generally fla-t unmolded sheet of acrylic followed 30 by thermoforming the acrylic sheet into the desired ~

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-1~43245 configuration. A layer of opaque-colored primer, which usually conta~ns 0.2 % by weight or more of a pigment such as a ~hite pigment is then applied by spraying or by hand to the pattern imprinted back of the acrylic sheet and then a layer of fiber glass reinforced polyester resin (FRP) containing 20 to 40 % by weight fiber glass is applied on top of the primer to reinforce the structure.
One of the outstanding features of the present ~ ' invention lies in applying the primer layer (Figure 3-33 in addition to the FRP reinforcement layer (Figure 3-4).
Without the primer layer, appIying FRP layer directly on ;`
the marble-patterned side of the sheet is liable to cause bubbles to form between the acrylic sheet and the layer. '- ' These bubbles and somtimes stray pieces of glass fiber are ' ' visible through the transparent acrylic sheet and render it exceedingly unsightly. Furthermore, the printed ink '' is a~fected by the polyester resin o~ the FRP and the marble ' '' pattern ~requently 'becomes deformed by bleeding of the ink or discolored.
Still another advantage oP applying the primer layer according to the present invention is that it increases ';~''' mechanical and physical strength of the enclosure as it brings '' about a stronger and more effective contact and adhesion be- '' tween the sheet, pattern and ~RP layer. Impact strength ~' test by the falling ball method proves that impact strength is'considerably improved by the present method over those ' without the primer layer. Also heat resistance test by hot -~
water method, comprising abrupt filling o~ hot water in the enclosure and maintaining it ~or a long time, establishe7 ' 30 that no peeling off of FRP layer, cracking of the sheet~ dis- `"

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~3Z45 coloration or deformation of the marble pattern occurs.
~ igures 1 and 2 are oblique views of a tub and basin, respectively.
Figure 3 is a sectional-'view of an acrylic sheet 1 and marble-pattern printed sheet 2 before thermoforming and also a sectional view after thermoforming showing primer layer 3 and FRP layer ~.
In Figures 1 and 2, the interior appearance of '~
the tub and the basin are shown with the marble pattern 10 visible at 1. The exterior fiber glass reinforced poly- ' ester layer is shown at 4. I
In ~igure 3, the flat aGrylic sheet is shown at i ' [Fig. 3(a)], to which the marble pattern 2 is applied [Fig. 3' (b)]. ~he marble-pattern printed sheet is thermoformed [~ig.
15 3(c)], and to the printed back side of the acrylic sheet the ~' primer layer 3 and FRP layer 4 are applied [Fig. 3(d)]. -Application of the marble pattern to one side of ' the acryli¢ sheet is accomplished by a simple process of printing or transfer printing of the desired marble pattern according to procedures known in the art. Advantageously, ' the desired marble pattern is printed on one side of the i`
acrylic sheet by means o~ a synthetic resin paint; such as ' ~ ' acrylic, polyvinyl chloride or alkyd gravure printing ink.
Once the mar'ble pattern has been applied to one ' ' 25 side of the flat acrylic sheet, the sheet is then thermo- '' ' .... . . ..
formed into the desired configuration with the marble patterned side on the outside of the formed con~iguration by means of known thermoforming techniques such as blow molding, vacuum pressure forming, match mold forming, etc.
~h'e actual conditions employed such as temperature, pressure '~ , ` ~ :,: ,,, ' . :-:'.' ~'. ' . ~

~ 43245 and time vary according to the thickness of the acrylic sheet employed and are easily determined by one skilled in the art. ~
Following molding or forming of the acrylic sheet into the desired shape, an opaque primer layer and a layer of FRP are applied by spraying or by hand to the printed back side of the acrylic sheet in order to provide rein-forcement and sufficient rigidity for the particular ar-~ticle being fabricated. As a resin for the primer layer, an unsaturated polyester, an acrylic resin such as a lower alkyl acrylate resin, or a mixture thereof is em- i -ployed. ~hus, it is suitable that the thickness of the primer layer is usually between 0.2-0.4 mm. for all enclosures and the fiber glass reinforced polyester layer will normally be between 3-5 mm. for bathtubs and 1.5-3 mm. for basins.
By carrying out the procedures of the present invention, an acrylio sheet is formed wherein a marble pattern occurs having no significant deterioration in quality due to thermoforming and in which sufficient rigidity can be obtained without requiring the use of thick pieces of acrylic sheet.
Typically, the acrylic sheets employed, according to the present invention, are, for example, polymethacrylate ester sheets such as polymethylmethacrylate sheet. The acrylic sheet has excellent transparency and, therefore9 the marble pattern has depth and is clearly visible.
These sheets which are employed according to the present invention will be between 1.5-8 mm. thick for bathtubs and 1-5 mm. thick for basins or sinks. This range of thickness .

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3;~45 has been found to provide excellent strength when supported with ~iber glass reinforced polyester resin. It is there-fore an advantage of the present invention that it is possible to employ a thinner and lighter acrylic sheet with superior appearance, and with superior performances relative to impact strength and hot water resistance.

xample :"
A number of sheets of trans~er printing paper -were prepared on which the facsimile of marble from a photograph of natural marble was imprinted with acrylic gravure ink. The trans~er print o~ the marble was then transferred onto a transparent polymethylmethacrylate sheet by the heat trans~er method at lsoa. A basin was then formed of the marble-patterned methacrylate sheet by vacuum ~orming at 170 to lsoc. so that the side having the printed pattern of marble was on the exterior o~ the basin. By means o~ a spray gun, a ooating composition consisting e~sentially of 50 parts by weight of polyethyl acrylate and 100 parts by weight of unsaturated polyester was applied as a coating over the printed pattern forming the exterior side o~ the basin. 1.5 % by weight o~ a white pigment was incorporated into the composition so that the coating acquired an opaque appearance. The thickness o~ the coating applied was approximately 0.3 mm.
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Also by means o~ a spray gun (or by hand), a coating com-position o~ 70 % by weight polyester resin reinforced by 30 % by weight glass fibers was then applied over the coating as the primer layer to reinforce the structure.
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~he thickness o~ the rein~orced polyester resin layer was .. ..

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~ 43Z45 about 2.0 mm.
~ he resulting basin produced according to the method described has a close resemblance to natural marble with the printed facsimile of the marble clearly seen through the transparent acrylic sheet. There were no scars, bubbles or stray pieces of glass fiber present.
In order to test the impact strength o~ the structure, a steel ball, weighing 198 grams was dropped on the basin from a height of 75 cm. No cracking, peeling ~ -or discoloration was however caused.
In order to test the heat resistance o~ the -structure, water heated to 92C. was poured into the basin and maintained at 82C. ~ 1C. for one hour and then drained ~ -~rom the basin. Water at room temperature (i.e., about 15 to 20C.) was then poured into the basin and maintained ~or ~ive minutes be~ore being~drained. This set o~ pro-cedures was repeated twenty times with no peeling or de-formation being obser~ed between the sheet and the layers and no deformation or discoloration of the marble pattern being noticeable. In another cycle of hot water tests, wherein the basin was ~illed with water which had been heated to 85C. and maintained in the basin until the tem-perature dropped to 60C., then drained off and replaced ;~
by water at room temperature for five minutes with the cycle of procedures being repeated one-hundred times, the `~ same results as previously indicated were obtained.
. ' ` Comparative ExamPle ~he procedures of Example were repeated except 30 that the primer layer coating was omitted and the fiber ;

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1~43Z45 glass reinforced polyester resin layer applied directly to the back or exterior of the structure.
~ he resulting structure,was observed to have a;
number of conspicuous air bubbles and stray pieces of 5 fiber glass present between the methacrylate sheet and the~ , fiber glass reinforced polyester layer. Further, the appearance of the marble pattern was not realistic and '' suffered by comparison with that found on the structure of the present invention prepared according to Example.
When the impact test using''a steel ball weighing 198 grams dropped ~rom a height of 75 cm. was repeated, a slight crack was observed at the point of impact with some discoloration due to peeling. ' , , When the hot water resistant tests were repeated as described in Example, no peeling deformation or dis-coloration was observed.
~he ~ollowing ~able compares othèr ~èatures of marble-patterned aorylic sheet produced by continuous ''' ca~ting and marble-patterned acrylic sheet prepared ~according to the method of the present invention:

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Comparison between Marble-patterned Continuous Casting Acrylic Sheet and Marble-patterned Acrylic Sheet of the ~resent invention . _ , _. . .
Continous Cast Marble Marble Patterned ~-Pattern Sheet of Prior Acrylic Sheet of Art Pre~ent Invention 1. Marble Pattern Monotonous and not Closest possible realistic. ~he facsimile o~
pattern is only in natural marble.
. 1 casting direction.

2. Usable space Pattern being partial- Full use i~ pos-ly too pale or other- sible.
- wise unfit, the usable space is limited.

. Availability Being mass-produced, Only printing work the kind3 are limited. on transparent One particular kind is acrylic sheets not always available which are obtain-in required quantity. able in desired quality can pro-vide desired mar-ble pattsrn, and various satisfact-ry articles are always available.

4. Quality Pigment being often No problem.
unevenly distributed within the sheet, it tend~ to deteriorate in localized areas.

5. Price Peing ~or a particular Cheaper even ad-use, the demand is ding the cost o~
limited and there~ore trans~er printing more expensiveO ~or a praotical number of sheet.
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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A molded article having the appearance of natural marble which comprises an interior sheet of molded transparent acrylic resin with a printed facsimile of marble applied to the Outside thereof, an intermediate layer comprising at least one resin selected from the group consisting of an unsaturated polyester resin and an acrylic resin applied to the back of said printed facsimile and an exterior layer of fiber glass reinforced polyester resin applied to said intermediate layer.

2. The molded article of Claim 1 wherein said transparent acrylic resin is polymethylmethacrylate.

3. The molded article of Claim 1 wherein said acrylic resin sheet is about 1 to 8 mm. thick and said layer of fiber glass reinforced polyester is about 1 to 5 mm. thick.

4. The molded article of Claim 1, 2 or 3 which is a tub.

5. The molded article of Claim 1, 2 or 3 which is a basin or sink.

6. The molded article of Claim 1, 2 or 3 wherein said intermediate layer also contains over 0.2% by weight white pigment.

7. The molded article of Claim 1, 2 or 3 wherein said glass reinforced polyester resin contains 20 to 40% by weight glass fibers.

8. A method of fabricating a molded article having the appearance of natural marble which comprises applying a printed facsimile of marble to the back of a generally flat sheet of acrylic resin, molding said imprinted acrylic resin sheet into a desired configuration, applying to the back of the printed facsimile an intermediate layer of at least one resin selected from the group consisting of an unsaturated polyester and an acrylic resin, and then applying a layer of fiber glass reinforced polyester resin to the back of the intermediate layer.

9. The method of Claim 8 wherein said fiber glass re-inforced polyester resin is applied by spraying or by hand.

10. The method of Claim 8 wherein said acrylic resin sheet is a sheet of transparent methylmethacrylate resin about 1 to 8 mm. thick and said fiber glass reinforced polyester resin is applied to a thickness of about 1 to 5 mm.

11. The method of Claim 8, 9 or 10 wherein said molded article is a tub.

12. The method of Claim 8, 9 or 10 wherein said molded article is a basin.

13. The method of Claim 8, 9 or 10 wherein said molded article is a sink.