CA2073682C - Process of forming fiber reinforced molded plastic articles and preforms therefor using a photosetting binder - Google Patents
Process of forming fiber reinforced molded plastic articles and preforms therefor using a photosetting binder Download PDFInfo
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- CA2073682C CA2073682C CA002073682A CA2073682A CA2073682C CA 2073682 C CA2073682 C CA 2073682C CA 002073682 A CA002073682 A CA 002073682A CA 2073682 A CA2073682 A CA 2073682A CA 2073682 C CA2073682 C CA 2073682C
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- Prior art keywords
- fibers
- preform
- ultraviolet light
- composition
- photohardenable
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B11/00—Making preforms
- B29B11/14—Making preforms characterised by structure or composition
- B29B11/16—Making preforms characterised by structure or composition comprising fillers or reinforcement
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
- B29C70/34—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core and shaping or impregnating by compression, i.e. combined with compressing after the lay-up operation
- B29C70/345—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core and shaping or impregnating by compression, i.e. combined with compressing after the lay-up operation using matched moulds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/003—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts characterised by the matrix material, e.g. material composition or physical properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2791/00—Shaping characteristics in general
- B29C2791/001—Shaping in several steps
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Reinforced Plastic Materials (AREA)
- Moulding By Coating Moulds (AREA)
- Laminated Bodies (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
The invention relates to a method of making fiber reinforced molded articles and preforms for use in the manufacture of such molded articles which includes the steps of applying a layer of reinforcing fibers, preferably glass fibers, on a preform mold surface which has a configuration corresponding to at least a portion of the final molded article, coating the fibers with an ultrav-iolet light curable composition which contains a photohardenable material polymerizable under UV light and a polymerization photoinitiator, exposing the coated fibers to UV light to cure the composition, and removing the resulting preform from the pre-form mold surface. The preform is subsequently used by placing it and a deformable plastic material in a mold, where an article containing the plastic reinforced by the fibers is formed.
Description
PROCESS OF FORMING FIBER REINFORCED MOLDED
PLASTIC ARTICLES AND PREFORMS THEREFORE
USING A PHOTOSETTING BINDER
BACKGROUND OF THE INVENTION
Field of the Invention The invention relates to the art of making fiber reinforced molded articles. Specifically, the invention relates to an improved process for forming fiber preforms for use in molding such articles in which an ultraviolet light, polymerizable, photohardenable composition is employed as a preform binder.
The use of preforms formed of glass or other fibers is a proven method of incorporating reinforcing fibers into complex shaped molds. Such preforms have been used for a number of years in the art of forming molded articles ,~~'i ~~~
utilizing matched die compression molds. When glass fibers are used as the reinforcing material, it has been common practice to chop glass fiber roving into shorter lengths. The fibers were then deposited onto preform molds which often were in the shape of a specially designed screen having a size, shape and configuration conforming to that of the part to be molded. Even distri-bution of the chopped glass fibers on the preform mold has been achieved by use of a vacuum behind the screen. The placement of holes and baffling the screen have also been utilized to control such distribution.
Heretofore, the binders used to bond the fibers together into a pref orm which can be handled have been of a heat curable type. Typically, such. binder compositions are based on unsaturated polyester resins dispersed or dissolved in water. Commonly, such resins are diluted to a 5 to 7$ solids concentration. This composition is sprayed on fibers and the binder composition is subsequently cured at elevated temperatures. Typically, a forced air oven is required for curing in which temperatures in the 350° to 500 °F (175°C to 260°C) range are utilized. The length of the curing cycle typically ranges between 20 seconds and several minutes, depending on the thickness of the preform and the air flow through the preform in the oven. Various manual and automated .
nG.~..''~~~~
methods have been used for this purpose. After curing, the preforms are moved from the screen, allowed to cool to ambient temperature, and then stored until they are used for molding.
' S
There are a number of disadvantages to these conventional methods of manufacturing preforms. Firstly, the procedures are relatively slow, in that typically the preform requires 1 to 3 minutes in the oven to cure, and up to an additional 30 seconds to cool down sufficiently for removal from the screen. Secondly, the heating required often bakes the over sprayed binder to a point that makes it very difficult to clean the preform screens and associated equipment. However, more importantly, the process is very energy intensive. Large motors are required to produce sufficient vacuum behind the screen and, thus, the airflow to and through the screen requires a large amount of energy. The high temperatures required to cure the binder and the high air flow required within the oven to remove the water and cure the binder is also highly energy intensive. In addition, the oven must have a relatively large exhaust stack to vent out the water vapor laden air. While it is possible to introduce heat exchangers to reduce some of the energy losses, this is not commonly done and, in any event, creates the need for additional equipment to deal with the condensed water _ 4 _ vapor. In addition to water vapor present in the exhaust air, there are often volatile organic compounds also pre-sent which are vaporized or atomized from the glass and binders in the oven. Because the legally allowable limits for such emissions are constantly being reduced, the in-stallation of expensive scrubbing equipment or, alterna-tively, the development of new preform binders and/or glass fiber sizing technology, is required.
It is an object of the present invention to overcome these problems by providing a new process of manufacturing preforms in which the curing can be performed at ambient temperatures. More specifically, the present invention involves the use of ultraviolet light to cure a UV
activated polymeric binder at or near ambient temperatures. The present invention thus eliminates the problems heretofore encountered with smoke generation and volatile organic compound emissions, reduces the difficulty of cleaning the equipment and, most importantly, greatly reduces the energy consumption of the process. A further advantage of the present invention is the achievement of an enormous increase in the speed of preform production by greatly reducing the time required to cure the preforms.
,.
An important object of the invention is to provide a very rapid and low energy consuming method for making fiber preforms which utilizes 100$ solids or very high solid content ultraviolet curable thermoset binders. A
further object of the invention is to provide a low energy consuming method of rapidly bonding or attaching fiber appendages to existing pref orms.
The present invention achieves the foregoing objects and advantages by providing a method of making fiber reinforced molded articles, which method may include the steps of first applying a layer of reinforcing fibers against a preform mold surface which has a configuration corresponding to that of the final molded article. The method then includes the step of coating the fibers with an ultraviolet light curable composition which contains a photohardenable material that is polymerizable under UV
light and a polymerization photoinitiator. The fibers are coated to a degree sufficient to coat the individual fibers without filling the interstices among the fibers.
>0 The thus coated fibers are then exposed to ultraviolet light to cure the composition. The resulting preform has the strength to be handled and stored for later use if desired, or transported in commerce.
' 25 Alternatively, it is an object of the present invention to provide a method of making fiber reinforced WO 91/10547 ~ . PGT/US90/07528 - 6 - ...
molded articles by coating the reinforcing fibers with an ultraviolet light composition, placing the coated fibers against a preform mold surface and curing them with .
ultraviolet light.
' When used, the pref orm is placed in a mold with a de-formable plastic material. The fiber preform and the plastic material are then molded together to form an article which consists of the plastic material containing the fibers therein as a fiber reinforcement. The fiber reinforced plastic article is then removed from the mold and processed further in accordance with conventional practice.
r~ny of the common UV curable resins and monomers may be used as the photohardenable material in practicing the invention. Examples of suitable materials are unsaturated polyesters, methacrylated and acrylated urethanes, methacrylated and acrylated epoxies, polyester acrylates, polyether acrylates, compositions containing allyl unsaturated and cationically polymerizable monomers and polymers in which W radiation is used to unblock a cationic catalyst.
Application of the photohardenable composition to the ' fibers on the mold is accomplished by spraying, roll coat WO 91 / 10547 ~ PCT/US90/07528 . _ 7 _ application or transfer roll coat application, or other common coating transfer methods. In a further aspect of the invention, a number of layers of glass matt may be treated individually and subsequently stacked to form a multilayered preform. It is also possible to coat several layers simultaneously and then cure them together. The amount of photohardenable material varies somewhat with the type of photohardenable material used as well with the type of fiber employed. In the case of glass fiber In preforms, the UV curable binder generally comprises between 0.2 and 15$ by weight of the total glass fibers.
The preferred binder content is in the 3 to 5$ by weight range.
In addition to glass fibers, various other fibers, such as carbon fibers, ceramic fibers, metal fibers, and plastic fibers such as polyester, polyethylene, aramide and other nylon fibers, may be used. The speed and uniformity of UV curing is improved significantly by the use of fibers which are optically clear and, thus, capable of transmitting ultraviolet light through them.
If desired, peroxides and/or metallic dryers may be incorporated in the photohardenable composition to improve curing of any areas which may not receive sufficient W
radiation. In accordance with conventional practice, the _ 8 _ ,.., photohardenable binder composition can be further formulated with fillers, pigments, dyes and additives to improve rheology, adhesion to the fibers, cure rate and other process parameters.
The shape of the preform is constructed by wrapping glass fibers around a mandrel or mold of a desired shape to preconstructed matts of chopped or continuous fibers, woven or non-woven fabrics, unidirectional or bidirectional stitched matts, or matts with sandwiched construction. The reinforcing fibers may be continuous or chopped. Alternatively, continuous or chopped glass fibers may be placed in a mold formed of a screen which is preferably transparent to W radiation. The preferred screen materials are glass or clear plastic, but other metallic or non-metallic materials may be substituted if desired. Generally, the screen or mandrel is preselected to conform to the shape of the finished article. However, in some cases it may be desirable to preform several components or sections of the finished article individually, and to later combine the sections into a final composite article.
The composition containing the photohardenable material is preferably 100% reactive. In any event, it should be a high solid content composition which contains WO 91/10547 ' . PGT/US90/07528 ~o~L~.. ~c.~~~."~T:~ ~~..
a photoinitiator. The composition should be responsive to and harden when subjected to UV radiation in the range of from 200 nm (nanometers) to 500 nm. The preferred range is from 250 nm to 400 nm.
Any source of UV radiation commonly used for curing thin films may be employed. Preferred sources are those with intensities of 200 watts or greater. Examples of such radiation sources are medium and high pressure mercury vapor lamps and electrodeless mercury vapor lamps.
Examples of such units are those manufactured by Ashdee Corp., (Evansville, Indiana) and Fusion Systems, Inc.
(Rockville, Maryland). Particularly advantageous for complex shapes are those sources which spread their energy 1S over a large area, such as pulse lamps with multidirectional reflectors (similar to units manufactured by IST America. Nashville, Tennessee). Especially suitable for concentrating energy when it is desired to attach a small appendage to a larger preform are sources directing energy by means of a flexible optical wand.
National Engineered Fiber Optic Systems, Inc. of Buffalo, New York, and Uvex, Inc. of Mountain View, California are suppliers of optical Wand W delivery systems.
Preforms prepared in accordance with the invention can be used to make various reinforced plastic articles. The . ~ - 10 - ,.~., plastic employed may either be thermoplastic or thermoset-ting. Examples of the finished articles are items used in the transportation, construction, furniture, recreational, marine, agricultural, and electrical industries. The fin-s fished articles are made by placing the preform together . ' with a thermosetting or thermoplastic material in an enclosed mold zone having a shape conforming to the finished product. The materials in the mold zone are then heated and compressed to form the molded shape. If the plastic deformable material is a thermoplastic, the material can be preheated to its deformation temperature and then forced within the mold cavity containing the preform to form the molded shape and thereafter allowed to cool and solidify. If a thermosetting plastic material is used, the plastic composition can be mixed, placed in the mold and heated to cure within the mold. The mold may be heated by any available conventional means, such as microwave, hot oil, steam, radiant heaters, sonic heaters, or the like.
Thermosetting materials include but are not limited to polyester, epoxy, polyurethane, polyisocyanurate, polyurea and phenolic molding resins.
An example of a thermosetting mixture is one containing approximately 55% by weight styrene containing ~ :~"'''~ fir' ~.~, to l4ci.._, ~~:,~~-r;. j .y polyester resin, 44~s by weight calcium carbonate and 0.5~
by weight of a benzoyl peroxide catalyst mixture and 0.5~
for an internal mold release composition. Such mixtures can be molded at pressures of approximately 200 to 2,000 psi (14 to 140 Kg per square centimeters) in a mold cavity heated to approximately 300° F (150°C) and will cure within the mold in approximately 1-2 minutes.
The invention will further be illustrated by means of i0 the following examples wherein all parts referred to are by weight, unless otherwise noted.
An ultraviolet curable binder containing 70 parts of urethane diacrylate oligomer (CHEMPOLm 19-4830, a product of Freeman Chemical Corporation), 25 parts trimethylolpropane trimethacrylate (Sartomer Co. SR 350), 2u 2 parts 2-hydroxy-2-methyl-1-phenyl-propane-1-one (E.
Merck, Darocure 1173). 3 parts N-methyldiethanolamine and 5 parts methyl ethyl ketone was applied to continuous strand glass at a concentration of approximately 3 grams binder per 33 grams glass.
Four layers of treated glass were sandwiched in an acrylic mold and exposed for 30 seconds on each side to 400 watts UV radiation from a portable Hoenle mercur y vapor ultraviolet lamp having a W output of 400 watts.
s , J
The resulting glass composite was stiff and held its shape well. No odor of uncured resin could be detected.
A small piece of woven glass was bonded (stitched) onto the composite using the same procedure.
An ultraviolet curable epoxy acrylate resin (CHEMPOL~
19-4837) prepared in accordance with the teaching of U.S.
Patent No. 4,216,306, issued August 5, 1980, and assigned to the assigner of the present invention, and containing benzophenone photoinitiator coreacted on its backbone and having a viscosity of 4900 cps at 25°C was applied to con-tinuous strand whirl matt glass by spraying or transferring from a thin film on polyester sheet.
Hy weighing the glass before and after treating with resin, it was determined that the binder constituted 4~.5$
of the total weight of the treated glass.
;, Flat sheets of treated glass were exposed to ultraviolet radiation emitted by one 200 watt per inch mercury vapor lamp in an Ashdee UV cure unit. The glass matt was passed under the UV lamp at a rate of 100 feet (30.Sm) per minute (approximately 0.4 second exposure).
Upon exiting from the UV unit, the matt was stiff and no odor of uncured resin could be detected.
One layer of glass matt treated with the composition of Example 2 was wrapped around a steel cylinder of 2 inch (S.lcm) diameter and secured with clear adhesive tape.
The part was rotated under the 200 watt per inch lamp for 1-2 seconds. Upon removal of the tape and cylinder, the glass matt was rigid and held its cylindrical shape.
The W curable binder system of Example 2 was applied to continuous strand glass by drawing down a film onto a glass plate, placing the glass fiber onto the film and rolling the glass with a hard rubber printer's roller to distribute the binder.
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The binder contents varied from 3$ to 5$ by weight of the total glass.
Four layers of the thusly treated glass were sandwiched in a two-part clear acrylic mold in the shape of an automotive bumper beam 24 inches (6lcm) in length, three inches (7.6cm) in width and three inches (7.6cm) in height.
The molded glass was then exposed by passing through the mold ultraviolet light emitted by a 118 watt per centimeter electrodeless lamp (Fusion Systems, Inc. "H
bulb"). After 15-30 seconds of exposure, the glass was rigid, non-tacky and retained its molded shape after removal of the acrylic mold.
EXAMPLE S
The procedure of Example 4 was followed except the source of ultraviolet light is a 400 watt mercury vapor lamp with an elliptical reflector manufactured by Dr.
Hoenle, West Germany. The glass was rigid, non-tacky and held its shape after removal from the mold.
- PCT~IIS 9 D~ ~ 7 ~ ~ ~
_ is - ~pEa~US
~" ~ 0 '7 3 fi 8 2 U ~ ~ ~ ~ V ~n92 The procedure of Example 4 was followed except the source of ultraviolet light is high pressure mercury short arc lamp with an output of 100 milliwatts/cm2 and light was delivered by a flexible optical light guide.
The unit was manufactured by National Engineered Fiber . Optics Systems, Inc. The glass was rigid, non-tacky and held its shape after 15-30 seconds exposure.
The application and curing procedures of Examples 4, 5 and 6 were repeated with a binder consisting of 70 parts epoxy acrylate oligomer (CHEMPOL~ 19-660, Freeman Chemical Corporation), 25 parts tripropylene glycol diacrylate (CL Industries, Georgetown, Illinois), 2 parts benzildimetyl ketal (Irgacure 651, Ciba Geigy Corporation), 3 parts N-methyl diethanolamine and 5 parts methyl ethyl ketone. The binder is a clear, colorless liquid with viscosity of 450 cps at 25QC.
After 15-30 seconds exposures, the glass composite was rigid, non-tacky and held the shape of the mold.
su~s~nu~E s,~E~
IPEA~ US
WO 91/10547 ' . PCT/US90/07528 - 16 - ,-.
The application and curing procedures of Examples 4, 5 and 6 were repeated with a polymerizable resin produced from combining acrylic acid, the diglycidyl ether of 1,4 butane diol and 3,3'. 4,4' benzophenone tetracarboxylic dianhydride (BTDA): The resin so prepared is a product of Freeman Chemical Corporation and is designated CHEMPOL~
19-4837.
1~
After 30-45 seconds, the glass composite was rigid, non-tacky and held its shape after removal from the acrylic mold.
A 3" x 5" triangular-shaped appendage was "stitched"
onto the glass composite of Example 7 by applying a band of the binder system of Example 1 to the point at which the fin-shaped appendage makes contact with the bumper beam and exposing the binder to the optical wand delivered W radiation from a 100 milliwatt per sq. cm. high pressure mercury vapor short arc lamp (Efos unit). After 5-10 seconds exposure, the fin Was tightly bonded to the bumper beam-shaped glass composite.
... _17_ G~~~~~,"~
The composition of Example 7 was applied to three layers of continuous strand glass matt by spraying with a low pressure spray gun manufactured by Croix Air Products, Inc. Binder content was 6$ by weight. The treated glass was exposed for 8 seconds to ultraviolet radiation of a 200 watt per inch mercury vapor lamp (Ashdee Model 25H/2A UV curing unit). Next, the cured 1(1 treated glass was placed into an 95.7cm x 45.7cm x 0.32cr:
aluminum resin transfer mold. A 2 part epoxy molding resin based on a diglycidyl ether of bisphenol A (Epon 828) and 1,2 diaminocyclohexane hardner (Shell Chemical Co.) was injected into the RTM mold under low pressure.
After maintaining the mold temperture at 66°C
for 1 hour, the hardening panel was removed from the mold and post cured for 2 hours at 135°C. Physical properties were determined and compared to a control panel prepared with 3 layers of untreated glass. Results are summarized in Table I.
'~ ~l ~;~ T a - 18 - -.., s~,~:,_,;'r, a The procedure of Example 10 was followed for treating and curing of preform binder. Three layer panels of glass with binder contents of 0%~ 4.6%, 6.8% and 8.4%
were thusly prepared. Each of the three layers of glass were placed in the RTM mold described in Example 10.
Next, a dicyclopentadiene-based polyester molding resin, (Stypol 40-0824 from Freeman Chemical Corp.) was injected under low pressure into the mold held at 54°C. The hardened Danel waS rPmnvorl frnm ti,c .".~,l,a after 60 seconds and post hardened for 2 hours at 135°C.
Physical properties of treated and untreated glass reinforced polyester composites are shown in Table II.
WO 91/10547 ~ . PCT/US90/07528 _ 1g _ TABLE I ~~~'~~~' w PHYSICAL PROPERTIES OF GLASS REINFORCED
EPOXY MOLDING COMPOUND
% PREFORM BINDER
Shore D Hardness 86 86 Impact Strength (Convert to Metric) Izod Notched (llb/in.) 10.33 8.97 Izod unnotched (llb/in.) 9.52 13.53 Flexural Strength (PSI) 1093.0 1465.8 Flexural Modulus (PSI) 52358.0 61390.4 Tensile Strength (PSI) 735.9 645.0 Tensile Modulus (PSI) 41157.2 43224.5 % Tensile Elongation 3.19 2.78 Heat Distortion Temperature (°C) X140 >140 - 2 0 - -.~., TABLE II
PHYSICAL PROPERTIES OF GLASS REINFORCED POLYESTER
MOLDING COMPOUND
$ BINDER
PROPERTY 0 4.6 6.8 8.4 Shore D Hardness 86 86 86 85 Impact Strength (Note must convert to metricfor Foreign Filing) IZOD Notched (lb./in.) 11.98 14..48 14.40 14.92 IZOD Unnotched (lb./in.) 16.27 22.38 18.99 18.96 Flexural Strength (PSI) 1669.5 2395.5 1922.6 1761.9 Flexural Modulus (PSI) 75611.4 87868.3 82800.1 73958.6 Tensile Strength (PSI) 831.7 920.2 1025.0 958.7 Tensile Modulus (PSI) 61695.7 64885.0 64895.2 57074.6 % Tensile Elongation 2.45 2.45 2.87 2.87 Heat Distortion Temp. (C) 7140 7140 7140 7140
PLASTIC ARTICLES AND PREFORMS THEREFORE
USING A PHOTOSETTING BINDER
BACKGROUND OF THE INVENTION
Field of the Invention The invention relates to the art of making fiber reinforced molded articles. Specifically, the invention relates to an improved process for forming fiber preforms for use in molding such articles in which an ultraviolet light, polymerizable, photohardenable composition is employed as a preform binder.
The use of preforms formed of glass or other fibers is a proven method of incorporating reinforcing fibers into complex shaped molds. Such preforms have been used for a number of years in the art of forming molded articles ,~~'i ~~~
utilizing matched die compression molds. When glass fibers are used as the reinforcing material, it has been common practice to chop glass fiber roving into shorter lengths. The fibers were then deposited onto preform molds which often were in the shape of a specially designed screen having a size, shape and configuration conforming to that of the part to be molded. Even distri-bution of the chopped glass fibers on the preform mold has been achieved by use of a vacuum behind the screen. The placement of holes and baffling the screen have also been utilized to control such distribution.
Heretofore, the binders used to bond the fibers together into a pref orm which can be handled have been of a heat curable type. Typically, such. binder compositions are based on unsaturated polyester resins dispersed or dissolved in water. Commonly, such resins are diluted to a 5 to 7$ solids concentration. This composition is sprayed on fibers and the binder composition is subsequently cured at elevated temperatures. Typically, a forced air oven is required for curing in which temperatures in the 350° to 500 °F (175°C to 260°C) range are utilized. The length of the curing cycle typically ranges between 20 seconds and several minutes, depending on the thickness of the preform and the air flow through the preform in the oven. Various manual and automated .
nG.~..''~~~~
methods have been used for this purpose. After curing, the preforms are moved from the screen, allowed to cool to ambient temperature, and then stored until they are used for molding.
' S
There are a number of disadvantages to these conventional methods of manufacturing preforms. Firstly, the procedures are relatively slow, in that typically the preform requires 1 to 3 minutes in the oven to cure, and up to an additional 30 seconds to cool down sufficiently for removal from the screen. Secondly, the heating required often bakes the over sprayed binder to a point that makes it very difficult to clean the preform screens and associated equipment. However, more importantly, the process is very energy intensive. Large motors are required to produce sufficient vacuum behind the screen and, thus, the airflow to and through the screen requires a large amount of energy. The high temperatures required to cure the binder and the high air flow required within the oven to remove the water and cure the binder is also highly energy intensive. In addition, the oven must have a relatively large exhaust stack to vent out the water vapor laden air. While it is possible to introduce heat exchangers to reduce some of the energy losses, this is not commonly done and, in any event, creates the need for additional equipment to deal with the condensed water _ 4 _ vapor. In addition to water vapor present in the exhaust air, there are often volatile organic compounds also pre-sent which are vaporized or atomized from the glass and binders in the oven. Because the legally allowable limits for such emissions are constantly being reduced, the in-stallation of expensive scrubbing equipment or, alterna-tively, the development of new preform binders and/or glass fiber sizing technology, is required.
It is an object of the present invention to overcome these problems by providing a new process of manufacturing preforms in which the curing can be performed at ambient temperatures. More specifically, the present invention involves the use of ultraviolet light to cure a UV
activated polymeric binder at or near ambient temperatures. The present invention thus eliminates the problems heretofore encountered with smoke generation and volatile organic compound emissions, reduces the difficulty of cleaning the equipment and, most importantly, greatly reduces the energy consumption of the process. A further advantage of the present invention is the achievement of an enormous increase in the speed of preform production by greatly reducing the time required to cure the preforms.
,.
An important object of the invention is to provide a very rapid and low energy consuming method for making fiber preforms which utilizes 100$ solids or very high solid content ultraviolet curable thermoset binders. A
further object of the invention is to provide a low energy consuming method of rapidly bonding or attaching fiber appendages to existing pref orms.
The present invention achieves the foregoing objects and advantages by providing a method of making fiber reinforced molded articles, which method may include the steps of first applying a layer of reinforcing fibers against a preform mold surface which has a configuration corresponding to that of the final molded article. The method then includes the step of coating the fibers with an ultraviolet light curable composition which contains a photohardenable material that is polymerizable under UV
light and a polymerization photoinitiator. The fibers are coated to a degree sufficient to coat the individual fibers without filling the interstices among the fibers.
>0 The thus coated fibers are then exposed to ultraviolet light to cure the composition. The resulting preform has the strength to be handled and stored for later use if desired, or transported in commerce.
' 25 Alternatively, it is an object of the present invention to provide a method of making fiber reinforced WO 91/10547 ~ . PGT/US90/07528 - 6 - ...
molded articles by coating the reinforcing fibers with an ultraviolet light composition, placing the coated fibers against a preform mold surface and curing them with .
ultraviolet light.
' When used, the pref orm is placed in a mold with a de-formable plastic material. The fiber preform and the plastic material are then molded together to form an article which consists of the plastic material containing the fibers therein as a fiber reinforcement. The fiber reinforced plastic article is then removed from the mold and processed further in accordance with conventional practice.
r~ny of the common UV curable resins and monomers may be used as the photohardenable material in practicing the invention. Examples of suitable materials are unsaturated polyesters, methacrylated and acrylated urethanes, methacrylated and acrylated epoxies, polyester acrylates, polyether acrylates, compositions containing allyl unsaturated and cationically polymerizable monomers and polymers in which W radiation is used to unblock a cationic catalyst.
Application of the photohardenable composition to the ' fibers on the mold is accomplished by spraying, roll coat WO 91 / 10547 ~ PCT/US90/07528 . _ 7 _ application or transfer roll coat application, or other common coating transfer methods. In a further aspect of the invention, a number of layers of glass matt may be treated individually and subsequently stacked to form a multilayered preform. It is also possible to coat several layers simultaneously and then cure them together. The amount of photohardenable material varies somewhat with the type of photohardenable material used as well with the type of fiber employed. In the case of glass fiber In preforms, the UV curable binder generally comprises between 0.2 and 15$ by weight of the total glass fibers.
The preferred binder content is in the 3 to 5$ by weight range.
In addition to glass fibers, various other fibers, such as carbon fibers, ceramic fibers, metal fibers, and plastic fibers such as polyester, polyethylene, aramide and other nylon fibers, may be used. The speed and uniformity of UV curing is improved significantly by the use of fibers which are optically clear and, thus, capable of transmitting ultraviolet light through them.
If desired, peroxides and/or metallic dryers may be incorporated in the photohardenable composition to improve curing of any areas which may not receive sufficient W
radiation. In accordance with conventional practice, the _ 8 _ ,.., photohardenable binder composition can be further formulated with fillers, pigments, dyes and additives to improve rheology, adhesion to the fibers, cure rate and other process parameters.
The shape of the preform is constructed by wrapping glass fibers around a mandrel or mold of a desired shape to preconstructed matts of chopped or continuous fibers, woven or non-woven fabrics, unidirectional or bidirectional stitched matts, or matts with sandwiched construction. The reinforcing fibers may be continuous or chopped. Alternatively, continuous or chopped glass fibers may be placed in a mold formed of a screen which is preferably transparent to W radiation. The preferred screen materials are glass or clear plastic, but other metallic or non-metallic materials may be substituted if desired. Generally, the screen or mandrel is preselected to conform to the shape of the finished article. However, in some cases it may be desirable to preform several components or sections of the finished article individually, and to later combine the sections into a final composite article.
The composition containing the photohardenable material is preferably 100% reactive. In any event, it should be a high solid content composition which contains WO 91/10547 ' . PGT/US90/07528 ~o~L~.. ~c.~~~."~T:~ ~~..
a photoinitiator. The composition should be responsive to and harden when subjected to UV radiation in the range of from 200 nm (nanometers) to 500 nm. The preferred range is from 250 nm to 400 nm.
Any source of UV radiation commonly used for curing thin films may be employed. Preferred sources are those with intensities of 200 watts or greater. Examples of such radiation sources are medium and high pressure mercury vapor lamps and electrodeless mercury vapor lamps.
Examples of such units are those manufactured by Ashdee Corp., (Evansville, Indiana) and Fusion Systems, Inc.
(Rockville, Maryland). Particularly advantageous for complex shapes are those sources which spread their energy 1S over a large area, such as pulse lamps with multidirectional reflectors (similar to units manufactured by IST America. Nashville, Tennessee). Especially suitable for concentrating energy when it is desired to attach a small appendage to a larger preform are sources directing energy by means of a flexible optical wand.
National Engineered Fiber Optic Systems, Inc. of Buffalo, New York, and Uvex, Inc. of Mountain View, California are suppliers of optical Wand W delivery systems.
Preforms prepared in accordance with the invention can be used to make various reinforced plastic articles. The . ~ - 10 - ,.~., plastic employed may either be thermoplastic or thermoset-ting. Examples of the finished articles are items used in the transportation, construction, furniture, recreational, marine, agricultural, and electrical industries. The fin-s fished articles are made by placing the preform together . ' with a thermosetting or thermoplastic material in an enclosed mold zone having a shape conforming to the finished product. The materials in the mold zone are then heated and compressed to form the molded shape. If the plastic deformable material is a thermoplastic, the material can be preheated to its deformation temperature and then forced within the mold cavity containing the preform to form the molded shape and thereafter allowed to cool and solidify. If a thermosetting plastic material is used, the plastic composition can be mixed, placed in the mold and heated to cure within the mold. The mold may be heated by any available conventional means, such as microwave, hot oil, steam, radiant heaters, sonic heaters, or the like.
Thermosetting materials include but are not limited to polyester, epoxy, polyurethane, polyisocyanurate, polyurea and phenolic molding resins.
An example of a thermosetting mixture is one containing approximately 55% by weight styrene containing ~ :~"'''~ fir' ~.~, to l4ci.._, ~~:,~~-r;. j .y polyester resin, 44~s by weight calcium carbonate and 0.5~
by weight of a benzoyl peroxide catalyst mixture and 0.5~
for an internal mold release composition. Such mixtures can be molded at pressures of approximately 200 to 2,000 psi (14 to 140 Kg per square centimeters) in a mold cavity heated to approximately 300° F (150°C) and will cure within the mold in approximately 1-2 minutes.
The invention will further be illustrated by means of i0 the following examples wherein all parts referred to are by weight, unless otherwise noted.
An ultraviolet curable binder containing 70 parts of urethane diacrylate oligomer (CHEMPOLm 19-4830, a product of Freeman Chemical Corporation), 25 parts trimethylolpropane trimethacrylate (Sartomer Co. SR 350), 2u 2 parts 2-hydroxy-2-methyl-1-phenyl-propane-1-one (E.
Merck, Darocure 1173). 3 parts N-methyldiethanolamine and 5 parts methyl ethyl ketone was applied to continuous strand glass at a concentration of approximately 3 grams binder per 33 grams glass.
Four layers of treated glass were sandwiched in an acrylic mold and exposed for 30 seconds on each side to 400 watts UV radiation from a portable Hoenle mercur y vapor ultraviolet lamp having a W output of 400 watts.
s , J
The resulting glass composite was stiff and held its shape well. No odor of uncured resin could be detected.
A small piece of woven glass was bonded (stitched) onto the composite using the same procedure.
An ultraviolet curable epoxy acrylate resin (CHEMPOL~
19-4837) prepared in accordance with the teaching of U.S.
Patent No. 4,216,306, issued August 5, 1980, and assigned to the assigner of the present invention, and containing benzophenone photoinitiator coreacted on its backbone and having a viscosity of 4900 cps at 25°C was applied to con-tinuous strand whirl matt glass by spraying or transferring from a thin film on polyester sheet.
Hy weighing the glass before and after treating with resin, it was determined that the binder constituted 4~.5$
of the total weight of the treated glass.
;, Flat sheets of treated glass were exposed to ultraviolet radiation emitted by one 200 watt per inch mercury vapor lamp in an Ashdee UV cure unit. The glass matt was passed under the UV lamp at a rate of 100 feet (30.Sm) per minute (approximately 0.4 second exposure).
Upon exiting from the UV unit, the matt was stiff and no odor of uncured resin could be detected.
One layer of glass matt treated with the composition of Example 2 was wrapped around a steel cylinder of 2 inch (S.lcm) diameter and secured with clear adhesive tape.
The part was rotated under the 200 watt per inch lamp for 1-2 seconds. Upon removal of the tape and cylinder, the glass matt was rigid and held its cylindrical shape.
The W curable binder system of Example 2 was applied to continuous strand glass by drawing down a film onto a glass plate, placing the glass fiber onto the film and rolling the glass with a hard rubber printer's roller to distribute the binder.
~o~''s7a~.d~~
The binder contents varied from 3$ to 5$ by weight of the total glass.
Four layers of the thusly treated glass were sandwiched in a two-part clear acrylic mold in the shape of an automotive bumper beam 24 inches (6lcm) in length, three inches (7.6cm) in width and three inches (7.6cm) in height.
The molded glass was then exposed by passing through the mold ultraviolet light emitted by a 118 watt per centimeter electrodeless lamp (Fusion Systems, Inc. "H
bulb"). After 15-30 seconds of exposure, the glass was rigid, non-tacky and retained its molded shape after removal of the acrylic mold.
EXAMPLE S
The procedure of Example 4 was followed except the source of ultraviolet light is a 400 watt mercury vapor lamp with an elliptical reflector manufactured by Dr.
Hoenle, West Germany. The glass was rigid, non-tacky and held its shape after removal from the mold.
- PCT~IIS 9 D~ ~ 7 ~ ~ ~
_ is - ~pEa~US
~" ~ 0 '7 3 fi 8 2 U ~ ~ ~ ~ V ~n92 The procedure of Example 4 was followed except the source of ultraviolet light is high pressure mercury short arc lamp with an output of 100 milliwatts/cm2 and light was delivered by a flexible optical light guide.
The unit was manufactured by National Engineered Fiber . Optics Systems, Inc. The glass was rigid, non-tacky and held its shape after 15-30 seconds exposure.
The application and curing procedures of Examples 4, 5 and 6 were repeated with a binder consisting of 70 parts epoxy acrylate oligomer (CHEMPOL~ 19-660, Freeman Chemical Corporation), 25 parts tripropylene glycol diacrylate (CL Industries, Georgetown, Illinois), 2 parts benzildimetyl ketal (Irgacure 651, Ciba Geigy Corporation), 3 parts N-methyl diethanolamine and 5 parts methyl ethyl ketone. The binder is a clear, colorless liquid with viscosity of 450 cps at 25QC.
After 15-30 seconds exposures, the glass composite was rigid, non-tacky and held the shape of the mold.
su~s~nu~E s,~E~
IPEA~ US
WO 91/10547 ' . PCT/US90/07528 - 16 - ,-.
The application and curing procedures of Examples 4, 5 and 6 were repeated with a polymerizable resin produced from combining acrylic acid, the diglycidyl ether of 1,4 butane diol and 3,3'. 4,4' benzophenone tetracarboxylic dianhydride (BTDA): The resin so prepared is a product of Freeman Chemical Corporation and is designated CHEMPOL~
19-4837.
1~
After 30-45 seconds, the glass composite was rigid, non-tacky and held its shape after removal from the acrylic mold.
A 3" x 5" triangular-shaped appendage was "stitched"
onto the glass composite of Example 7 by applying a band of the binder system of Example 1 to the point at which the fin-shaped appendage makes contact with the bumper beam and exposing the binder to the optical wand delivered W radiation from a 100 milliwatt per sq. cm. high pressure mercury vapor short arc lamp (Efos unit). After 5-10 seconds exposure, the fin Was tightly bonded to the bumper beam-shaped glass composite.
... _17_ G~~~~~,"~
The composition of Example 7 was applied to three layers of continuous strand glass matt by spraying with a low pressure spray gun manufactured by Croix Air Products, Inc. Binder content was 6$ by weight. The treated glass was exposed for 8 seconds to ultraviolet radiation of a 200 watt per inch mercury vapor lamp (Ashdee Model 25H/2A UV curing unit). Next, the cured 1(1 treated glass was placed into an 95.7cm x 45.7cm x 0.32cr:
aluminum resin transfer mold. A 2 part epoxy molding resin based on a diglycidyl ether of bisphenol A (Epon 828) and 1,2 diaminocyclohexane hardner (Shell Chemical Co.) was injected into the RTM mold under low pressure.
After maintaining the mold temperture at 66°C
for 1 hour, the hardening panel was removed from the mold and post cured for 2 hours at 135°C. Physical properties were determined and compared to a control panel prepared with 3 layers of untreated glass. Results are summarized in Table I.
'~ ~l ~;~ T a - 18 - -.., s~,~:,_,;'r, a The procedure of Example 10 was followed for treating and curing of preform binder. Three layer panels of glass with binder contents of 0%~ 4.6%, 6.8% and 8.4%
were thusly prepared. Each of the three layers of glass were placed in the RTM mold described in Example 10.
Next, a dicyclopentadiene-based polyester molding resin, (Stypol 40-0824 from Freeman Chemical Corp.) was injected under low pressure into the mold held at 54°C. The hardened Danel waS rPmnvorl frnm ti,c .".~,l,a after 60 seconds and post hardened for 2 hours at 135°C.
Physical properties of treated and untreated glass reinforced polyester composites are shown in Table II.
WO 91/10547 ~ . PCT/US90/07528 _ 1g _ TABLE I ~~~'~~~' w PHYSICAL PROPERTIES OF GLASS REINFORCED
EPOXY MOLDING COMPOUND
% PREFORM BINDER
Shore D Hardness 86 86 Impact Strength (Convert to Metric) Izod Notched (llb/in.) 10.33 8.97 Izod unnotched (llb/in.) 9.52 13.53 Flexural Strength (PSI) 1093.0 1465.8 Flexural Modulus (PSI) 52358.0 61390.4 Tensile Strength (PSI) 735.9 645.0 Tensile Modulus (PSI) 41157.2 43224.5 % Tensile Elongation 3.19 2.78 Heat Distortion Temperature (°C) X140 >140 - 2 0 - -.~., TABLE II
PHYSICAL PROPERTIES OF GLASS REINFORCED POLYESTER
MOLDING COMPOUND
$ BINDER
PROPERTY 0 4.6 6.8 8.4 Shore D Hardness 86 86 86 85 Impact Strength (Note must convert to metricfor Foreign Filing) IZOD Notched (lb./in.) 11.98 14..48 14.40 14.92 IZOD Unnotched (lb./in.) 16.27 22.38 18.99 18.96 Flexural Strength (PSI) 1669.5 2395.5 1922.6 1761.9 Flexural Modulus (PSI) 75611.4 87868.3 82800.1 73958.6 Tensile Strength (PSI) 831.7 920.2 1025.0 958.7 Tensile Modulus (PSI) 61695.7 64885.0 64895.2 57074.6 % Tensile Elongation 2.45 2.45 2.87 2.87 Heat Distortion Temp. (C) 7140 7140 7140 7140
Claims (38)
1. A method of making fiber reinforced molded articles comprising:
a. applying a layer of reinforcing fibers on a preform mold surface which has a configuration corresponding to at least a portion of the final molded article, b. coating at least some of said fibers with an ultraviolet light curable composition which contains a photohardenable material polymerizable under UV light and a polymerization photoinitiator, to a degree sufficient to coat said fibers without filling the intersticies among said fibers, c. exposing said coated fibers to UV light to cure substantially all of said composition to form an essentially rigid preform, d. removing the preform from said preform mold surface, e. placing said preform and a deformable plastic material in a mold, f. molding said preform and said plastic material together to form an article comprising said plastic with said fibers contained therewithin as a reinforcement, and g. removing the resulting fiber reinforced plastic article from said mold.
a. applying a layer of reinforcing fibers on a preform mold surface which has a configuration corresponding to at least a portion of the final molded article, b. coating at least some of said fibers with an ultraviolet light curable composition which contains a photohardenable material polymerizable under UV light and a polymerization photoinitiator, to a degree sufficient to coat said fibers without filling the intersticies among said fibers, c. exposing said coated fibers to UV light to cure substantially all of said composition to form an essentially rigid preform, d. removing the preform from said preform mold surface, e. placing said preform and a deformable plastic material in a mold, f. molding said preform and said plastic material together to form an article comprising said plastic with said fibers contained therewithin as a reinforcement, and g. removing the resulting fiber reinforced plastic article from said mold.
2. A method according to Claim 1, wherein uncoated reinforcing fibers are initially applied to the mold surface and then coated with said ultraviolet light curable composition prior to exposure to said UV light source.
3. A method according to Claim 1, wherein said reinforcing fibers are pre-coated with said ultraviolet light curable composition prior to being applied to said preform mold surface prior to exposure to said UV light source.
4. A method according to Claim 1, wherein said photohardenable composition is selected from the group consisting of unsaturated polyesters, methacrylated urethanes, acrylated urethanes, acrylated epoxies, polyether acrylate resins, acrylated polyesters, compositions containing allyl unsaturated and cationically polymerizable compositions containing a blocked cationic catalyst which can be unblocked by UV
radiation, and mixtures of the above photohardenable compositions and polyethylenically unsaturated organic monomers.
radiation, and mixtures of the above photohardenable compositions and polyethylenically unsaturated organic monomers.
5. A method according to Claim 1, wherein said preform mold comprises a screen or a material transparent to UV radiation having a shape conforming to that of the part to be molded.
6. A method according to Claim 1, wherein said preform mold comprises a mandrel around which said fibers are deposited.
7. A method according to Claim 1, wherein said fibers transmit ultraviolet light.
8. A method according to Claim 1, wherein said fibers are glass fibers, and said photohardenable composition is coated thereon in an amount of about 0.2 to 15% by weight of said fibers.
9. A method according to Claim 1, wherein said composition also contains a peroxide curable material and a peroxide catalyst.
10. A method of making a rigid, fiber reinforcement preform for use in making fiber reinforced molded articles comprising:
a. applying a layer of reinforcing fibers on a preform mold surface which has a configuration corres-ponding to at least a portion of the final molded article, b. coating said fibers with an ultraviolet light curable composition which contains a photohardenable material polymerizable under UV light and a polymerization photoinitiator, to a degree sufficient to coat said fibers without filling the interstices among said fibers, c. exposing said coated fibers to UV light to cure substantially all of said composition to form an essentially rigid preform, and, d. removing the preform from said preform mold surface.
a. applying a layer of reinforcing fibers on a preform mold surface which has a configuration corres-ponding to at least a portion of the final molded article, b. coating said fibers with an ultraviolet light curable composition which contains a photohardenable material polymerizable under UV light and a polymerization photoinitiator, to a degree sufficient to coat said fibers without filling the interstices among said fibers, c. exposing said coated fibers to UV light to cure substantially all of said composition to form an essentially rigid preform, and, d. removing the preform from said preform mold surface.
11. A method according to Claim 10, wherein uncoated reinforcing fibers are initially applied to the mold surface and then coated with said ultraviolet light curable composition prior to exposure to said UV light source.
12. A method according to Claim 10, wherein said reinforcing fibers are pre-coated with said ultraviolet light curable composition prior to being applied to said preform mold surface prior to exposure to said UV light source.
13. A method according to Claim 10, wherein said photohardenable composition is selected from the group consisting of unsaturated polyesters, acrylated urethanes, acrylated epoxies, polyether acrylates, acrylated polyester resins, compositions containing allyl unsaturation and cationically polymer-izable compositions containing a blocked cationic catalyst which can be unblocked by UV radiation, and mixtures of the above photohardenable compositions and polyethylenically unsaturated organic monomers.
14. A method according to Claim 10, wherein said preform mold comprises a screen or a material transparent to UV radiation having a shape conforming to that of the part to be molded.
15. A method according to Claim 10, wherein said preform mold comprises a mandrel around which said fibers are deposited.
16. A method according to Claim 10, wherein said fibers transmit ultraviolet light.
17. A method according to Claim 10, wherein said fibers are glass fibers, and said photohardenable composition is coated thereon in an amount of about 0.2 to 15% by weight of said fibers.
18. A method according to Claim 10, wherein said composition also contains a peroxide curable material and a peroxide catalyst.
19. A method of making a rigid, fiber reinforced preform useful in making a fiber reinforced molded article, the method comprising the steps of:
a. shaping a flexible mat of reinforcing fiber into a configuration corresponding to at least a portion of the molded article;
b. coating the fibers of the mat with an ultraviolet light curable composition which contains a photohardenable material polymerizable under ultraviolet light and a polymerization photoinitiator to a degree sufficient to coat the fibers of the mat without filling the intersticies among the fibers; and c. exposing the coated fibers to ultraviolet light to cure substantially all of the composition to form an essentially rigid preform.
a. shaping a flexible mat of reinforcing fiber into a configuration corresponding to at least a portion of the molded article;
b. coating the fibers of the mat with an ultraviolet light curable composition which contains a photohardenable material polymerizable under ultraviolet light and a polymerization photoinitiator to a degree sufficient to coat the fibers of the mat without filling the intersticies among the fibers; and c. exposing the coated fibers to ultraviolet light to cure substantially all of the composition to form an essentially rigid preform.
20. The method of Claim 19 in which the reinforcing fibers transmit ultraviolet light.
21. The method of Claim 20 in which the reinforcing fibers of the mat are glass fibers, and the photohardenable composition is coated on the glass fibers in an amount of about 0.2 to 15% by weight of the glass fibers.
22. A method of making a fiber reinforcement mat, the method comprising the steps of:
a. forming reinforcing fiber into a shaped structure;
b. coating the reinforcing fibers with an ultraviolet light curable composition which contains a photohardenable material polymerizable under ultraviolet light and a polymerization photoinitiator to a degree sufficient to coat the reinforcing fibers without filling the interstices among the reinforcing fibers; and c. exposing the coated reinforcing fibers to ultraviolet light to cure substantially all of the composition whereby the fibers are bonded to one another to form the mat.
a. forming reinforcing fiber into a shaped structure;
b. coating the reinforcing fibers with an ultraviolet light curable composition which contains a photohardenable material polymerizable under ultraviolet light and a polymerization photoinitiator to a degree sufficient to coat the reinforcing fibers without filling the interstices among the reinforcing fibers; and c. exposing the coated reinforcing fibers to ultraviolet light to cure substantially all of the composition whereby the fibers are bonded to one another to form the mat.
23. The method of Claim 22 in which the reinforcing fibers transmit ultraviolet light, and the photohardenable composition is substantially 100%
reactive.
reactive.
24. The method of Claim 23 in which the reinforcing fibers are glass fibers, and the photohardenable composition is coated onto the glass fibers in an amount of about 0.2 to 15% by weight of the glass fibers.
25. A preform made by the process of Claim 19.
26. A preform made by the process of Claim 20.
27. A preform made by the process of Claim 21.
28. A mat made by the process of Claim 22.
29. A mat made by the process of Claim 23.
30. A mat made by the process of Claim 24.
31. The method of Claim 1 in which the reinforcing fibers comprise a plurality of mats, and the photohardenable binder is applied to the mat such that after cure the mats are bonded to one another to form a substantially rigid preform having substantially the same shape as the mold surface.
32. The method of Claim 10 in which the reinforcing fibers are a plurality of mats, and the photohardenable binder is applied to the mats such that after cure the mats are bonded to one another to form a substantially rigid preform having substantially the same shape as the mold surface.
33. A method of making a rigid, composite fiber reinforcement preform for use in making fiber reinforced molded articles, the method comprising:
a. applying to a composite preform mold surface i. a rigid preform conforming to at least a portion of the mold surface, the mold surface corresponding to at least a portion of the final molded article, and ii. reinforcing fibers, the fibers and preform in at least particle contact with both one another and the mold surface;
b. coating the fibers and at least that part of the preform that is in contact with the fibers with an ultraviolet light curable composition which contains a photohardenable material polymerizable under ultraviolet light, which is substantially 100%
reactived, and a polymerization photoinitiator to a degree sufficient to coat the fibers and preform without filling the interstices among the fibers or the fibers that form the preform;
c. exposing the coated fibers and preform to ultraviolet light for less than about 45 seconds to cure substantially all of the composition to form an essentially rigid, composite preform; and d. removing the composite preform from the composite mold surface.
a. applying to a composite preform mold surface i. a rigid preform conforming to at least a portion of the mold surface, the mold surface corresponding to at least a portion of the final molded article, and ii. reinforcing fibers, the fibers and preform in at least particle contact with both one another and the mold surface;
b. coating the fibers and at least that part of the preform that is in contact with the fibers with an ultraviolet light curable composition which contains a photohardenable material polymerizable under ultraviolet light, which is substantially 100%
reactived, and a polymerization photoinitiator to a degree sufficient to coat the fibers and preform without filling the interstices among the fibers or the fibers that form the preform;
c. exposing the coated fibers and preform to ultraviolet light for less than about 45 seconds to cure substantially all of the composition to form an essentially rigid, composite preform; and d. removing the composite preform from the composite mold surface.
34. A fiber reinforced molded article made by the process of Claim 1.
35. A method of making fiber reinforced molded articles comprising:
a. applying a layer of reinforcing fibers on a preform mold surface which has a configuration corresponding to at least a portion of the final molded article;
b. coating at least some of said fibers with an ultraviolet light curable composition which contains a photohardenable material which is substantially 100%
reactive and is polymerizable under UV light, and a polymerization photoinitiator, to a degree sufficient to coat said fibers without filling the interstices among said fibers;
c. exposing said coated fibers for less than about 45 seconds to UV light to cure substantially all of said composition to form an essentially rigid preform;
d. removing the preform from said preform mold surface;
e. placing said preform and a deformable plastic material in a mold;
f. molding said preform and said plastic material together to form an article comprising said plastic with said fibers contained therewithin as a reinforcement; and g. removing the resulting fiber reinforced plastic article from said mold.
a. applying a layer of reinforcing fibers on a preform mold surface which has a configuration corresponding to at least a portion of the final molded article;
b. coating at least some of said fibers with an ultraviolet light curable composition which contains a photohardenable material which is substantially 100%
reactive and is polymerizable under UV light, and a polymerization photoinitiator, to a degree sufficient to coat said fibers without filling the interstices among said fibers;
c. exposing said coated fibers for less than about 45 seconds to UV light to cure substantially all of said composition to form an essentially rigid preform;
d. removing the preform from said preform mold surface;
e. placing said preform and a deformable plastic material in a mold;
f. molding said preform and said plastic material together to form an article comprising said plastic with said fibers contained therewithin as a reinforcement; and g. removing the resulting fiber reinforced plastic article from said mold.
36. A method of making a rigid, fiber reinforcement preform for use in making fiber reinforced molded articles comprising:
a. applying a layer of reinforcing fibers on a preform mold surface which has a configuration corresponding to at least a portion of the final molded article;
b. coating said fibers with an ultraviolet light curable composition which contains a photohardenable material which is substantially 100%
reactive and is polymerizable under UV light, and a polymerization photoinitiator, to a degree sufficient to coat said fibers without filling the interstices among said fibers;
c. exposing said coated fibers to UV light for less than about 45 seconds to cure substantially all of said composition to form an essentially rigid preform; and d. removing the preform from said preform mold surface.
a. applying a layer of reinforcing fibers on a preform mold surface which has a configuration corresponding to at least a portion of the final molded article;
b. coating said fibers with an ultraviolet light curable composition which contains a photohardenable material which is substantially 100%
reactive and is polymerizable under UV light, and a polymerization photoinitiator, to a degree sufficient to coat said fibers without filling the interstices among said fibers;
c. exposing said coated fibers to UV light for less than about 45 seconds to cure substantially all of said composition to form an essentially rigid preform; and d. removing the preform from said preform mold surface.
37. A method of making a rigid, fiber reinforced preform useful in making the fiber reinforced molded article, the method comprising the steps of:
a. shaping a flexible mat of reinforcing fiber into a configuration corresponding to at least a portion of the molded article;
b. coating the fibers of the mat with an ultraviolet light curable composition which contains a photohardenable material which is substantially 100%
reactive and is polymerizable under ultraviolet light, and a polymerization photoinitiator, to a degree sufficient to coat the fibers of the mat without filling the interstices among the fibers; and c. exposing the coated fibers to ultraviolet light for less than about 45 seconds to cure substantially all of the composition to form an essentially rigid preform.
a. shaping a flexible mat of reinforcing fiber into a configuration corresponding to at least a portion of the molded article;
b. coating the fibers of the mat with an ultraviolet light curable composition which contains a photohardenable material which is substantially 100%
reactive and is polymerizable under ultraviolet light, and a polymerization photoinitiator, to a degree sufficient to coat the fibers of the mat without filling the interstices among the fibers; and c. exposing the coated fibers to ultraviolet light for less than about 45 seconds to cure substantially all of the composition to form an essentially rigid preform.
38. A method of making a fiber reinforcement mat, the method comprising the steps of:
a. forming reinforcing fiber into a shaped structure;
b. coating the reinforcing fibers with an ultraviolet light curable composition which contains a photohardenable material which is substantially 100%
reactive and is polymerizable under ultraviolet light, and a polymerization photoinitiator to a degree sufficient to coat the reinforcing fibers without filling the interstices among the reinforcing fibers;
and c. exposing the coated reinforcing fibers to ultraviolet light for less than about 45 seconds to cure substantially all of the composition whereby the fibers are bonded to one another to form the mat.
a. forming reinforcing fiber into a shaped structure;
b. coating the reinforcing fibers with an ultraviolet light curable composition which contains a photohardenable material which is substantially 100%
reactive and is polymerizable under ultraviolet light, and a polymerization photoinitiator to a degree sufficient to coat the reinforcing fibers without filling the interstices among the reinforcing fibers;
and c. exposing the coated reinforcing fibers to ultraviolet light for less than about 45 seconds to cure substantially all of the composition whereby the fibers are bonded to one another to form the mat.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US46338890A | 1990-01-11 | 1990-01-11 | |
| US463,388 | 1990-01-11 | ||
| US60999790A | 1990-11-07 | 1990-11-07 | |
| US609,997 | 1990-11-07 | ||
| PCT/US1990/007528 WO1991010547A1 (en) | 1990-01-11 | 1990-12-19 | Process of forming fiber reinforced molded plastic articles and preforms therefor using a photosetting binder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2073682A1 CA2073682A1 (en) | 1991-07-12 |
| CA2073682C true CA2073682C (en) | 2002-02-19 |
Family
ID=27040639
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002073682A Expired - Lifetime CA2073682C (en) | 1990-01-11 | 1990-12-19 | Process of forming fiber reinforced molded plastic articles and preforms therefor using a photosetting binder |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0510097A1 (en) |
| JP (1) | JPH05505352A (en) |
| KR (1) | KR920703286A (en) |
| AU (1) | AU660407B2 (en) |
| CA (1) | CA2073682C (en) |
| WO (1) | WO1991010547A1 (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69304042T2 (en) * | 1990-07-12 | 1996-12-19 | C A Lawton Co | Method and device for the production of structurally reinforced preforms, with energetic temporary gluing or stitching |
| US5192387A (en) * | 1990-11-05 | 1993-03-09 | The C.A. Lawton Company | Method of making preforms |
| US5217654A (en) * | 1992-01-30 | 1993-06-08 | The C. A. Lawton Company | Two-stage mat forming preforming and molding process |
| ZA93819B (en) * | 1992-02-24 | 1993-10-15 | Cook Composites & Polymers | Process of making a rigid multi-layer preform |
| FR2700171B1 (en) * | 1993-01-07 | 1995-02-24 | Vetrotex France Sa | Process for the preparation of glass-resin prepregs intended for the manufacture of composite parts. |
| FI102945B1 (en) * | 1995-02-24 | 1999-03-31 | Bioxid Oy | Polymer-fiber prepreg, process for its preparation and use thereof |
| US5882462A (en) * | 1996-02-02 | 1999-03-16 | Dow-United Technologies Composite Products | Method for fabricating a corrugated composite channel |
| AU4487497A (en) * | 1997-09-19 | 1999-04-12 | Boeing Company, The | Method for fabricating a corrugated composite channel |
| RU2148060C1 (en) * | 1997-12-08 | 2000-04-27 | Институт проблем лазерных и информационных технологий РАН | Method of hardening photopolymerizing acrylic oligomer-based composition by initiating polymerization on radiation coating hardening installations |
| KR20020088794A (en) * | 2001-05-21 | 2002-11-29 | 유림산업 주식회사 | Reinforced plastic have granite pattern and manufacture method thereof |
| DE10161773A1 (en) * | 2001-12-15 | 2003-06-26 | Bayerische Motoren Werke Ag | Method for producing a three-dimensionally shaped fiber composite plastic component |
| US20080156212A1 (en) * | 2004-03-30 | 2008-07-03 | Hiroshi Yamada | Hollow Cylindrical Printing Element |
| TW200716361A (en) * | 2005-07-27 | 2007-05-01 | Mitsubishi Heavy Ind Ltd | Rtm process |
| DE102006048920B3 (en) * | 2006-10-10 | 2008-05-21 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Electrically conductive lightweight component and method for its production |
| DE102008028865B4 (en) * | 2008-06-19 | 2015-04-02 | Airbus Defence and Space GmbH | Process for the production of fiber composite profile components, as well as use of such manufactured fiber composite profile components |
| JP2012001665A (en) * | 2010-06-18 | 2012-01-05 | Asahi Organic Chemicals Industry Co Ltd | Sheet material, piping member, and method of manufacturing sheet material |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US442587A (en) * | 1890-12-09 | Fender for street-cars | ||
| SE420991B (en) * | 1978-02-13 | 1981-11-16 | Scandinavian Glasfiber Ab | KIT FOR PREPARATION OF FORMULA OF GLASS FIBER ARMED HARDWARE |
| DE2931737A1 (en) * | 1979-08-04 | 1981-02-26 | Basf Ag | METHOD FOR PRODUCING MOLDED BODIES FROM UNSATURATED POLYESTER RESINS |
| US4692291A (en) * | 1980-04-14 | 1987-09-08 | Union Carbide Corporation | Molding method using fast curing fiber reinforced, low viscosity thermosetting resin |
| DE3109424A1 (en) * | 1981-03-12 | 1982-10-28 | Herbert 7140 Ludwigsburg Schreiber | METHOD FOR THE PRODUCTION OF FIBER REINFORCED PLASTIC OBJECTS AND PREPREG FOR ITS IMPLEMENTATION AND ITEMS OBTAINED THEREOF |
| DE3636755A1 (en) * | 1986-10-29 | 1988-05-05 | Basf Ag | METHOD FOR PRODUCING HOLLOW BODIES |
-
1990
- 1990-12-19 CA CA002073682A patent/CA2073682C/en not_active Expired - Lifetime
- 1990-12-19 EP EP91903515A patent/EP0510097A1/en not_active Withdrawn
- 1990-12-19 AU AU72203/91A patent/AU660407B2/en not_active Expired
- 1990-12-19 JP JP91503521A patent/JPH05505352A/en active Pending
- 1990-12-19 WO PCT/US1990/007528 patent/WO1991010547A1/en not_active Ceased
- 1990-12-19 KR KR1019920701645A patent/KR920703286A/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| KR920703286A (en) | 1992-12-17 |
| AU660407B2 (en) | 1995-06-29 |
| AU7220391A (en) | 1991-08-05 |
| EP0510097A1 (en) | 1992-10-28 |
| JPH05505352A (en) | 1993-08-12 |
| CA2073682A1 (en) | 1991-07-12 |
| WO1991010547A1 (en) | 1991-07-25 |
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