JPH04232702A - Fiber-contained material overlaid with new fiber - Google Patents

Abstract

PURPOSE: To obtain a smooth surface with an abundant resin by forming reinforcing fibrous strands such as continuous and/or chopped strands on one layer and having the reinforcing strands in contact with a layer of binder resin capable of being set so as to be deposited thereon. CONSTITUTION: After multi-thread preform-chopped roving 16, 17, and 18 are applied to a preform screen 7, single-thread glass fiber forming 27, 28, and 29 are cut into chops having a length of 2 in. to be released to a tube 13. They are exposed to high-pressure air at zones 50, 51 in the tube 13, which is introduced from nozzles 58, 73 to the tube at a pressure of about 90 to 100 psig. The resulting fiber 81 is then transferred to a preform screen 7 which has already formed a reinforcing layer so as to be deposited on the reinforcing layer such that the thickness is about 20 mils (0.051 cm) or the density is 0.25 oz per sq ft.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to a new veil of fiber-containing materials in fiber-containing reinforcement for polymeric materials and to a process for their preparation. More specifically, the invention provides:
The present invention relates to the preparation of preforms for use in molding structurally liquid components using a novel process. Still more particularly, the present invention relates to preforms for the molding of structurally liquid components formed of discrete lengths of strands and filaments that provide a molded product with strength as well as excellent surface properties. .

0002

BACKGROUND OF THE INVENTION Fiber-containing reinforcement materials for polymeric matrix reinforcements are used in a number of processes, including hand layering, spray layering, and liquid component formation. In the latter molding process, the preform is applied to the field of structurally liquid component molding, or liquid component molding or structural reaction injection molding, or resin transfer molding, or resin injection molding (all hereinafter referred to as LCM). used. The method used to prepare the LCM preform is:
Well known in the field. Our US Pat. No. 4,923,731 discloses a process used to make a novel preform with increased edge strength. A novel preform screen for use in this process is also disclosed. In the prior art of LCM, strands, rovings or integrated fiber bundles, each containing multiple fibers (hereinafter referred to as
strands) are deposited in discrete lengths on the preformed screen. The strands are typically in contact with a binder resin before being deposited onto the preform screen. After being deposited on the preform, the resin-containing preform is set or at least partially cured by heating without losing its shape so that the screen shapes the preform into the shape of the final molded part.
Can be removed from that screen. After being removed from the screen, the preform is placed into a thermoformer. After closing the molding machine, the low viscosity matrix resin is injected into the heated molding machine. The temperature is sufficient to gel and harden the matrix resin that forms the structural LCM product.

[0003] To apply the strands to the preform screen, cutting the strands, transferring them to the preform screen, and applying binder resin may be performed in one integrated process. It has also been practiced for a long time. Our aforementioned patent discloses a process that combines a rotary multiple station preform machine to accomplish this. This process involves applying strands of reinforcing material to the screen used to form the shape of the preform. If the shape produced by this process is to be made into a preform for subsequent molding as a final part where a smooth surface is desired, a surface mat typically covers the preform. This mat, commonly referred to as a veil mat, is a highly filamentated, integrated mat, typically 10 to 30 mils thick, and typically has more resin than the reinforcement preform covering this surface. Highly demanding. There are problems with the use of this veil mat, which is applied by roll. This is because they typically need to be cut and shaped by hand, which is very costly. This cost discourages the use of LCM processes that rely on the final use of the preform. Folds and wrinkles are common in the use of bale mats when the shape of the preform is complex. Often, this folding and wrinkling affects the moldability and final appearance of the preform and matrix resin. Furthermore, the surfaces of the preform and molded product can become uneven due to the tension of this veil mat during molding.

0004

Therefore, while it is desirable to provide preforms with good structural and surface properties, industrial producers are still struggling to find a cost-effective preform without sacrificing quality. It is necessary to supply the product at a certain price. The need to reduce the labor costs involved in cutting and shaping bale mats into preforms of cut strands for surface reinforcement, and these preforms accomplished with bale mats. There is still a need to improve the surfaces of.

[0005]

SUMMARY OF THE INVENTION In accordance with the present invention, high quality molded surface properties and excellent reinforcement properties are provided.
A process is provided that significantly reduces the cost of producing fiber-containing reinforcements. Thus, in the present invention, strands of reinforcement fibers, such as continuous and/or cut strands, are formed in one layer. The strands of reinforcement are deposited against and over a layer of settable binder resin. When the required amount of reinforcement strands is placed in a reinforcement layer, the successive individual strands are passed through a fluid medium and rest on the surface provided by the reinforcement strands collected in the layer. be done. The provision of individual strands is continuous with fibers that are not substantially chemically bonded or integrated to the extent that the fibers in conventional strands, such as the individual strands that provide reinforcement. Use natural strands.

[0006] Such individual strands are removed from the supply body, cut and transferred to the intended reinforcing layer;
It is then brought into contact with a high-velocity fluid. This fluid breaks the strands into individual strands, creating a multiplicity of individual filaments or fibers (hereinafter referred to as fibers) into slightly integrated but loosely bound bundles. It's fast enough. The individual fibers are then fluid-displaced and placed on the strands of reinforcement already deposited in the reinforcement layer. The fibers are fed into this layer until they substantially cover the reinforcing strands. These fibers are normally brought into contact with a binder resin while being moved. However, in some cases the addition of binder resin may not be necessary. If the reinforcement strands already present in the reinforcement layer contain sufficient resin,
This resin can keep the fibers in place where they would collide with the reinforcing strands. Once the surface of this reinforcing layer is covered with fibers to the desired thickness, the fiber flow is discontinued and the reinforcement with fibers placed on the bale surface is partially set, e.g. Fiber-reinforced polymeric parts can be prepared and used for reinforcing polymeric materials.

In a particular aspect of the invention, the reinforcing material of the invention is a preform for use in LCM. In this aspect, the cut strands of reinforcement are fed to a cutting machine where they are cut into individual lengths. The cut strands are then placed in a flowable medium and placed on the surface of the preform screen. Individual lengths of reinforcement strands are brought into contact with and deposited onto a settable binder resin so as to rest on the surface of the screen. The drop in pressure due to the suction of the preform machine causes the strands to coalesce into each other as they impact the screen of the preform. When the requisite amount of strands of reinforcement is placed on the preform screen, successive individual strands from the second feed are passed through the flowable medium to form the collected reinforcement on the preform screen. is placed on the surface provided by the strands. The supply of individual strands has fibers that are not substantially chemically bonded or integrated to the extent that the fibers in conventional strands, such as the individual strands that supply reinforcement. Use continuous strands.

These strands of the second feed are cut and transferred to the target preform, breaking the strands to separate them from a slightly integrated but loosely bonded bundle into individual filaments or fibers ( The fibers (hereinafter referred to as fibers) are contacted with a high velocity flow of fluid at a velocity sufficient to render them multiplicity. The individual fibers are fluid-displaced and placed on top of the reinforcing strands already deposited on the preform. Fibers are applied to this surface until they substantially cover the reinforcing strands. These fibers are typically contacted with a binder resin while being transferred to a preform machine. However, in some cases the addition of binder resin is not necessary. If the reinforcing strands already present on the preform screen contain enough resin, with the decrease in pressure this resin can hold the fibers where it impinges on the reinforcing strands. Once the preform surface is covered with the desired thickness of fibers, the flow of fibers is stopped. The preform can then be peeled off from the preform screen, at least partially set, and molded into parts that match the shape of the screen.

Fibers and strands contemplated for use in the practice of this invention include polyethylene, polyethylene terephthalate (PET), polyvinyl acetate, nylon, polypropylene, polyphenylene sulfide,
Included are synthetic, organic and inorganic fibers such as glass, carbon and silica; and aramid fibers or mixtures of one or more of these fibers. However, it is not limited to these. In a preferred embodiment of the invention, glass strands and fibers are used.

[0010] Among the intended objects of the invention is the use of fiber-laden bale mats with reinforcing fibers or strand materials of any type as described herein. For example, the bale material of the present invention can be used in hand plying operations, spray plying operations and LCM processes with continuous and/or cut glass fiber strand reinforcing fiber-containing materials.

[0011] The present invention will be explained in detail below using the drawings.

[0012] As shown in FIG. 1, a preform screen 7 is attached to a preform machine, such as a rotary multi-station preform machine (shown schematically at 12), in the Assignee (Carley and Schell) US patent. No. 4,923,731, entitled "Novel Preform Screens and Preform Products," the preforms may be formed by carrying out the prior art techniques. The above documents are incorporated into this application. The preform screen 7 is placed on a rotating frame 21 of the preform machine 12. The preform machine 12 has a plurality of stations 22
, 23, 24 and 25. The preform screen 7 rests on the rotating frame 21 of the preform machine by using suitable fasteners (not shown) such as nuts or bolts in holes provided in the screen frame 5 (FIG. 2). . As shown in FIGS. 2 and 3, the screen 7
has a number of holes 8 in it. A frame 5 forms the periphery of the screen, and around the edge of the screen 7 there is a solid wall member 6 projecting from the frame 5. An insertion opening 9 is provided in the wall 6 at one end of the screen 7. The frame 21 is attached to a shaft 26 and rotates by the shaft 26. Shaft 26 is rotated by a motor (not shown). The preform machine 12 has a shaft 26, as described below.
is designed to rotate in 90° increments.

A station 23 is installed on the upper part of the rotating frame member 21.
In communication is chamber 11, which is typically a heated air oven-filled chamber. screen 7
After the upper preform has been slid from the working station 22 into the opening of the station 23, the screen 7
The binder resin in the upper cut strand 2 is exposed to a heated fluid, such as air, for a time sufficient to at least partially set. This set of resins can be partially cured if the resin is thermoset, or melt and flow if the resin is thermoplastic. Thereby, the binder resin and the strand are integrated into the preform 1 of the cut strand.

Station 24 is an unloading station, at which the preforms 1 on the screen 7 that have been rotated from the oven section of the chamber 11 are peeled off from the preform screen 7. At this station 24, the preform 1 is inserted through an insertion opening 9 provided in the wall 6 of the preform screen 7 (details shown in FIG. 2).
After the tool is inserted, the preform 1 is gently lifted off the surface of the screen 7 and removed. The preform screen 7 located at station 25 is just a spare and is moved to the position of station 22,
At that station the preform screen 7 is filled and moved to the next station 23, where the chamber 11
solidified inside. The chamber 10 of the station 25 has an exhaust fan (not shown) and the preform machine 12
Air is constantly drawn from the station 22 to create a suction over the screen 7 to help coat the cut strands thereon.

At a point in front of the station 22, there is a cylindrical member 13 and a chopper unit 1 that are involved in discharging cut materials.
There is a cutting machine 20 to which 9 is attached. The cylinder is equipped with a binder resin sprayer 15 near its tip to which a resin supply body (not shown) is connected. This sprayer 1
5 sends the binder resin 14 into the cut strand 2 discharged from the tip of the tube 13 to coat the cut strand with the binder resin. Suitable examples of binder resins include, but are not limited to, thermoset and thermoplastic polymers that are compatible with the base resin reinforcing the preform. These binder polymers can be powders, filaments, liquids, or solutions, suspensions or emulsions with suitable carriers such as water. Examples of these types of binder polymers include poly(vinyl acetate), polyesters, polyurethanes, and the like. As shown in the figure, the cutting machine 20
At the start of operation, the strands 16, 17 and 18 are fed to a chopper unit 19 and, after being cut, the cut strands 2 are sent to the tube 13. The resulting cut strand 2 is propelled onto a screen 7 by means of a blast of fluid, typically air. This fluid is supplied to tube 13 from a blower (shown in FIG. 4) attached to or located within cutting machine 20. The chopper unit 19, the binder resin sprayer 15 and the blower are preferably operated from a central control panel which automatically starts and similarly automatically stops all equipment in a timed sequence for the desired purpose. Dispense the amount of binder resin and strands required for the preform. The cylinder 13 is movable in the vertical and horizontal planes and is capable of clockwise and counterclockwise rotational movements, so that the strands can be fed to any desired position on the screen 7.

After the cut strand 2 from the first feed has been formed from the strands 16, 17 and 18 and deposited to the desired thickness on the screen 7, the feed to the chopper is stopped and the strands 16, 17 and 18 are removed from the chopper. Removed from unit 19. The strands 27, 28 and 29 from the second feed are cut into individual lengths as they pass through the chopper unit 19 and are treated with high velocity fluid as they pass through the tube 13. The velocity of the fluid is sufficient to break up the strands into fiber components. The obtained fibers are then transferred from the tube 13 to the screen 7.
is sprayed onto the layer of cut strands 2 already on the screen. Generally, the fibers in the strands of the second supply have a fiber diameter of about 1 μm to about 35 μm.
but preferably has a diameter of about 15 to about 25 microns.
m, and smaller diameters can also be used.

The operation of the system for providing fibrillated filaments or fibers is shown in more detail in FIG. As shown in FIG. 4, the strands 27, 28 and 29 pass through the guide holes 60 on the support 61 to the chopper unit
9 and passed through chopping rollers 40 and 41 driven by a motor 42 and a belt 43. The cut strands 80 in the chopper unit 19 fall into the hopper 46 and exit from the blower 47 through the opening 49 in the wall.
The tube 13 is transported by a fluid, typically air, which is directed through the hopper 46 . The cut strands 80, in this case loosely held together by just a small chemical treatment to keep the fibers organized into strands with each other during chopping, are forced forward through the tube 13. At this time, in this embodiment, the fluid passes through two high-speed fluid processing zones 50 and 51 provided within the cylinder 13. The tube 13 is attached to the hopper 46 with a flexible tube 55 attached to the tube 13 with a flange 53, and the tube 13 is attached to the hopper with a flange 54.
is preferably hard.

The high-velocity fluid inlet section 50 is provided with a tube 56 having an inlet 57 for introducing fluid into it and ending in a nozzle 58 at its end in the section 50 . The nozzle 58 is oriented downwardly and at least slightly forwardly so that the fluid exiting therefrom is directed to all fibers passing through the section 50 and these fibers are then ejected towards the exit of the tube. is preferable. Area 5
0 is housed in a connector, shown schematically at 62, which is connected to the tube 13 and has a collar 64 through which the tube 56 passes. The tube 56 is kept in the collar 64 by a suitable plug 65 which acts as a seal against fluid leakage. The second connector 70 is the connector 64
A second high-velocity fluid zone 51 is formed in the interior of the connector 70, which is also connected to the tube 1.
3 and forms part of it. The connector 70 is
It has a tube 71 having an inlet 72 and a nozzle 73 at its end. Connector 70 is further provided with a plug 76 and a collar 75 that seal against fluid leakage from tube 71 and nozzle 73. As the cutting strand 80 shown in the hopper passes through zones 50 and 51 in tube 13, it contacts high velocity fluid entering these zones through nozzles 58 and 73. This contact shatters the cut, loosely bound bundle of strands 80 into filamentary or fibrous components, so that a stream of fibrillated fibers 81 is created within the tube 13 which exits the tube 13. Then, the preform screen 7, which has already been supplied with cut and reinforced strands 2, is coated. The fiber 81 that has left the tube 13 is
The binder resin can be sprayed with the binder resin from the binder resin sprayer 15 or, in some cases, directly onto the preform surface of the resin-rich cut strand, thus allowing the fiberized fibers to accumulate thereon. The necessary binder resin is supplied.

Operating the rotating system shown in FIG. 1 and using the specific cylindrical donor device 13 shown in FIGS. 1 and 4, a preform is manufactured as follows. Using a preform screen as depicted in FIGS. 2 and 3, the screen 7 is attached to the frame 21 of the rotary preform machine 12 shown in FIG. The same screens 7 provided in preform station 22 are also installed in stations 23, 24 and 25 of the rotary preform machine. The heater (not shown) in the chamber 11 is activated. The strands 16, 17 and 18 are connected to the chopper unit 19 of the cutting machine 20, and the chopper unit 19 and the blower 47 are activated, preferably simultaneously, to begin the operation. By operating the motor 42 of the chopper unit 19, the strands 16, 17 and 18
passes between roller choppers 40 and 41 included in the chopper unit 19 and is cut therein,
It passes into the lower part or hopper 46, from where the blower 47
It is sent to the cylinder 13 by. During this part of the operation, air inlet tubes 56 and 71 are not operating with the blower. Therefore, only air from the blower 47 directs the cut strand 2 into the tube 13 and to its outlet end. As the cut strand 2 exits the tube 13, it is sprayed with binder resin from the binder resin spray supply nozzle 15 and is intimately coated with binder resin. The resin-coated cut strands 2 are then placed on the surface of the screen 7. The flow tube 13 has a flexible tube 55 attached to the hopper 46 so that it can be moved in any direction, allowing the operator or robot to move the screen 7 until the entire area of the screen 7 is coated to the desired degree. Can send strands to the surface. The extent of this can be determined experimentally for each preform, and the desired properties of the final reinforcement will depend on the amount of reinforcement desired, but suitable microprocessing equipment will Can be programmed. As a result, when the desired amount of reinforcement has been applied to the screen 7, the blower 47 and the strand supply are automatically turned off.

[0020] Once the desired amount of cut strands 2 has been applied to the screen 7, the operation of the blower is interrupted and the operation of the chopper unit 19 is likewise interrupted. The second chopper or again the first chopper now has a strand 27 as another supply to the chopper unit 19;
Pass through 28 and 29. Strands 27, 28 and 2
9 is fed to rotary choppers 40 and 41 and cut into hopper 46. At the same time, the blower 47 located on the cutting machine 20 is activated, so that the resulting cut strand 80 is forced into the tube 13 by air or other suitable fluid. As the cut strand 80 passes through the tube 13, it passes through two successive zones 50 and 51 of high velocity fluid, preferably a zone supplied with high velocity air. As the strands 80 enter these high velocity zones, air exiting the nozzle 58, for example in the zone 50, impinges on the cut strands, essentially filamentizing them. Filamentization involves attacking integrated bundles of fibers in the form of cut strands and breaking them into fiber components. Of course, it will be appreciated that a strand contains a number of fibers loosely bound together by a chemical treatment agent known as a binder or size. The velocity of the high velocity air depends in part on the chemical treatment agent present on the fibers in the strand, and may also depend on the composition of the strand, ie, the number of fibers in the strand. Typically, the greater the amount of chemical treatment agent present in the fibers, and the type of chemical treatment agent, and the greater the number of fibers in the strand, the higher the air velocity must be to achieve filamentation. . Essentially the speed is the speed required to filamentize the cut strands from the second feed. Cutting strand 80 and area 5
The fiber 81 made therefrom passes through the second high velocity fluid section 51. If necessary, air, preferably at high pressure, is now again bombarded with cut strands 80 and fibers 81 coming from section 50 in order to filamentize the remaining cut strands 80. The obtained fibers 81 then exit from the outlet of the tube 13, where they are again suitably coated with binder resin 14, and then the filamentary material 81 is already deposited on the screen 7 by moving the tube 13 appropriately. Cut strand 2
sent on the surface of Once the desired thickness of fiber 81 is obtained, the supply of strands 27, 28 and 29 to chopper unit 19 is stopped. The blower 47 also stops like the ventilation pipes 56, 57 and 71, 72.

At this point, the rotary preform machine is rotated counterclockwise and the screen 7, on which the binder resin bound preform is deposited, is moved upwardly from station 22 to station 23 in chamber 11. . Along with this rotation, the screen 7 of the station 25, that is, the position where the screen 7 can be placed, is moved.
At the station 22 is placed the screen 7 on which the next preform is formed. Furthermore, along with this rotation, the screen 7 that was previously at the unloading station 24,
That is, the position where the screen 7 can be placed is moved downward and placed in the position of the station 25. Similarly, the screen 7 with its partially set preform is removed from the station 23, and at the station 24 the screen 7 is replaced, ie in a position where it can be placed. The screen 7 with the preform is rotated and enters a chamber 11 containing a heated fluid, preferably air, so that the filaments 81 on the screen 7 and the binder resin contained in the cut strands 2 are at least partially set. The preform remains there for a sufficient time at a temperature sufficient to cause the rotary preform to be turned on again. This screen 7 is transferred from the partial setting station 23 to the unloading station 24. At this point the preform is cooled, prepared for subsequent shaping and removed from station 24 by entry of suitable tools through insertion holes 9 shown in preform screen 7 in FIG. The preform is then removed from the screen.

One of the features of the invention that is important in the operation of the process according to the invention is that the strands 27, 28 and 29
to form fiber 81 strands with little or no chemical treatment or sizing. On the other hand, the glass fiber forming process requires the application of chemical treatments such as size and binders in order to make them compatible with some type of matrix resin material in which they will ultimately be used as reinforcement. Any sizing formula generally known to size fibers by those skilled in the art may be used for strand 2.
7, 28 and 29, where the amount of size or dry residue of size is strictly controlled. The amount is the minimum amount that will keep the strands together during chopping, but will cause the strands to filamentate during the in-process gusts. Accordingly, the amount of sizing present in the strands is from about 0.02 to about 0.5% by weight based on loss on ignition (LOI), preferably used at less than 0.1% of LOI. Strand 27,
Preferably, the sizing for 28 and 29 is just a lubricant. The lubricant provides adequate protection to the fibers forming these strands while they are processed into strand shape from the forming bush and assembled into some kind of known cylindrical package. Furthermore, the lubricant is supplied to the chopper unit 19 shown in the figure.
Provides sufficient consolidation force to the fibers forming the strands 27, 28 and 29 to keep them bundled together until used. Typically, lubricants used for this purpose are Cation-X, an alkylimidazoline reaction product of tetraethylenepentamine and stearic acid; Emery 6717, a partially amidated polyalkyleneimine; and Fiberlube 1575. , a cationic lubricant. The strands may have small amounts of coupling agents such as organofunctional silanes and/or film-forming polymers in addition to or instead of lubricants. Any of these materials known to those skilled in the art as chemical treatment agents for glass fibers may be used. Some non-exclusive examples are film-forming polymers such as poly(vinyl acetate), poly(vinyl alcohol), poly(oxyalkylene), polyester, poly(urethane) and epoxy; and γ-aminopropyltriethoxysilane. , γ-methacryloxy-propyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyl-triethoxysilane and ureido-modified aminosilanes. The amount of lubricant and/or, if present, coupling agent and/or film-forming polymer present in the strands is determined by the loss on ignition ( L
from about 0.02 to about 0.5% by weight based on the LOI, preferably less than 0.1% of the LOI.

[0023] In structural preforms made in accordance with the present invention, for use as reinforcing materials, the cut strand layer in the preform typically has a thickness of 125 to 10
00mil (0.125~1inch; 0.3175~
It has a thickness of 2.54 cm). The fibers in the reinforcing strands have a diameter between 5 and 35 μm, preferably between 9 and 27 μm, and in preferred embodiments using glass fibers, fibers with a diameter of 9 to 14 μm are used in multi-strand constructions, i.e. A roving yarn is used. The outer surface layer of the preform, made of discrete lengths of fiber, is typically 5 to 50 mm thick.
l, preferably 10 to 30 mil (0.010 to
0.030 inch; 0.025 to 0.076 cm). Generally, the filamentable strands have a diameter of 1 to 35 μm, preferably 9 to 25 μm, and in preferred embodiments using glass fibers, 15 to 25 μm in diameter, and are constructed of single strands, preferably 2000 threads. It is a single strand of roving yarn that looks like a bundle. The thickness of this surface layer is 50 mil (
If it exceeds 0.050inch; 0.127cm),
Problems arise regarding the resin requirements of the preform when it is made into a molded body, and such thicknesses are generally not beneficial. However, 5-30mil (0.005-0.03
0 inch) (0.0127 to 0.076 cm) provides compatibility for the underlying reinforcing layer and for the matrix resin injected into the molded body as it is made. It will be done. Furthermore, using fibers forming a surface in this range will provide a molded member with a smooth surface approaching that of a grade A stainless steel finish.

Structural members that can be constructed according to the invention include:
It can have any size or shape. The complexity of the shape is not a burden to those producers who require a surface forming layer as a coating. This burden is suitably reserved for corners, edges, and complex bends by the mounting fibers used as the second feed of the present invention, ensuring that the fibers evenly cover the shape of these areas. be reduced in order to The finished preform has minimal, if any, wrinkles or other irregularities caused by efforts to shape the bale mat into this surface shape. Additionally, because the fibers are placed separately on a screen to form the fiberized fiber surface, any surface material on preforms made in accordance with the present invention is free from elongation, which is often seen with conventional methods. not exist.

[0025] To further illustrate the invention and its utility, and to demonstrate the smooth surfaces obtained by practicing the invention, the preferred form of the process of the invention and the products produced thereby are illustrated. Reference is made to the examples given below as well as comparative examples for other similar products.

[0026]

[Example] (Comparative Example 1) A 16" x 36" preform was prepared using a conventional multi-filament preform roving on a fiber preform machine similar to that shown in Figure 1. A 16" x 16" test panel was molded. Glass fiber preform rovings 16, 17, and 18 are fed to a chopper unit 19, cut into 2-inch lengths, and passed through a tube 13 onto a preform screen 7 attached to a rotating preform machine. was deposited to a calculated density of 4 ounces per square foot. This density is 0.125 inches (0.3175 cm
) corresponds to a glass content of approximately 28 percent by weight in the test panel. The binder resin 14 applied to the cut strand 2 from the nozzle 15 when it is ejected from the tube 13 includes P from Rohm & Haas.
olyco2113 general purpose poly(vinyl acetate) was used. Once the reinforced glass had finished depositing the cut strands 2, the preform screen 7 was rotated to station 23 in the plenum 11, where the heated air in the plenum partially cured the resin. Screen 7 was then moved to station 24 and the preform was removed from screen 7. Furthermore 16”x16”
After cutting to size, molding was performed. This preform can be heated from 273°F to 300°F (134°C to 14°C).
This is done in a heated mold at a temperature of 9°C), which results in a thickness of 0.
．． A 125 inch (0.3175 cm) test panel was prepared. Next, the surface roughness of this panel was measured using a surface profilometer. The results are shown in Table 1.

(Comparative Example 2) As a second comparative example, the same 16”x test panel as that produced in Comparative Example 1 was
A 16" test panel was made under the same conditions as Comparative Example 1, with the following exceptions: After the cut strands were deposited on the screen and at least partially set, station 23 of the rotary preform machine was used. A veil mat was placed on the surface of the preform prior to rotation.
0.020 inch; 0.051 cm) was used. Thereafter, similarly, the preform with the veil mat was rotated to the station 23 of the plenum 11 and partially set there. Next, it was rotated to station 24 and the premat was taken out. The resulting preform with a bale matte surface is placed in a heated mold;
By molding with matrix resin, the thickness is approximately 0.
．． A 125 inch (0.3175 cm) test panel was prepared. The surface roughness of this panel was measured using a surface profilometer. The results are shown in Table 1.

EXAMPLE 1 In one embodiment of the present invention, which constitutes the best mode, a 16" x 16" test panel was prepared using a fiber placement preform machine similar to that shown in FIG. Prepared. Same multi-filament preform glass fiber rovings 16, 17, and 1 as in Comparative Example 1
8 was used. These were applied to a 16" x 36" preform screen 7 and 2 inch long chops were deposited on the screen to a density of 4 ounces per square foot. In this way, the multi-filament preform cut roving yarn 16, 1
After applying 7 and 18 to the preform screen 7, the single glass fiber rovings 27, 28, and 2
9 was cut into 2 inch long chops and discharged into tube 13. In the tube 13, high pressure air was collided in zones 50 and 51 (see FIG. 4). High pressure air is about 90-100
It was introduced into the tube through nozzles 58 and 73 at a pressure of psig. The resulting fibers 81 are then fed to the preform screen 7, which already has a reinforcing layer formed thereon, and is deposited approximately 20 mils (0.051 cm) thick on top of this reinforcing layer.
, or a density of 0.25 ounces per square foot. The cut strands 2 and fibers 81 were spray coated with Polyco resin 2113 from Rohm & Haas as a binder resin from unit 15 as they were discharged from tube 13 to screen 7 . The fibers used were approximately 22 microns in diameter and were coated with Cation X and Union Carbide Chemi as a silane binder.
cal corp. (A-1100) silane, at an LOI level of 0.5 weight percent of these lubricants and binders, based on the weight of the strand. It is spun. The resulting preform on screen 7 is rotated to station 23 in the plenum of chamber 11 where it is heated to a temperature of approximately 250°F (121°C) until the binder resin of the preform partially sets. heated for sufficient time. The preform machine is then rotated further and moved to station 24 where the preform is removed and cut into 16" x 16" sheets and placed in a heating mold.
Test panels were prepared by molding at approximately 300°F (149°C). The resulting molded panel was measured with a profilometer to determine the average surface roughness. The results are shown in Table 1.

[0029]

[Table 1] Average surface roughness RA of RTM panel*1 surface flophylometer measurement panel
*2 Comparative Example 1 1
00 Comparative Example 2
41 Example 1
The 46*1 panel was molded in a P20 steel test panel mold and finished with SPE #2. The matrix resin system is a polyester resin formulation (Ashla
Aropol 2036). What is RTM?
resin transfer mold
ing).

*2 Average surface roughness measured with Feinpruf's Perthometer model M4P. A lower number indicates a smoother surface. The unit is microinch.

As can be seen from Table 1, the spray-applied veiled fiber mounting preform of Example 1 was obtained using the expensive veil mat of Comparative Example 2 on the flat final part. Similar profilometer measurements were obtained. The surface properties required for any practical application were comparable (to those of Comparative Example 1). On the other hand, the surface roughness of the preform of Comparative Example 1, which did not use veil mat or spray application of veil, was insufficient for most cosmetic applications.

Example 2 To further evaluate the ability to use LCM molding, a comparison of properties with another method, here sheet molding compound (SMC), is performed. Panels reinforced with fiber-mounted preforms and filamentated spray-coated veiling were prepared as in Example 1. This preform was molded with a polyester matrix resin containing a filler and a surface smoothing agent. The resin is Ash, which is a low profile resin typically used in class A SMC formulations.
Aropol 50405 from Land was used. This resin was mixed with calcium carbonate filler in a 1:1 ratio. Panels prepared in this manner with a glass content of about 30 percent were measured using a profilometer. The results are shown in Table 2.

(Comparative Example 3) A fiber mounting preform was prepared according to Comparative Example 1. The resulting preform was molded with Ashland's Aropol 50405 resin mixed 1:1 with calcium carbonate filler. The results are shown in Table 2. Standard type SMC
The average surface roughness of SMC molded panels formed from the same low-profile resin mold in a molding machine and molded into panels of the same size as Example 2 and Comparative Example 3 with a glass content of approximately 27% was measured using a profilometer. Measured at The results are shown in Table 2.

[0034]

[Table 2] Average surface roughness RA of RTM panel*1 surface flophylometer measurement panel
*2 Comparative Example 3
16 Example 2
8SMC*3
5*1 The panel was molded in a P20 steel test panel mold and finished with SPE #2. The resin system is a low profile resin formulation (Ashla
Aropol50405/CaCo3, 1/1)
Met.

*2 Feinpruf persometer (
Average surface roughness measured with Perthometer) model M4P. A lower number indicates a smoother surface. The unit is microinch.

*3 SMC panels are high voltage, that is,
800 for less than 200psi in RTM panels
Compression molded at psi.

As is clear from the table, the molded panels in which the surface of the preform reinforcement was veiled by spray coating for fiber placement exhibited an average surface roughness similar to that of the SMC molded panels. This is an RTM molded panel made according to the method of the invention described in Example 2. This is true even if SMC molding uses a higher pressure than RTM molding. A molded product with a smooth surface can be produced by increasing the molding pressure. It is clear from Table 2 that RTM panels are comparable to SMC panels in surface properties.

The advantage of spray-applied bales over regular commercially available bale mats is that when applied to non-flat shapes, bale mats must be cut and carefully shaped into preform shapes. Additionally, spray applied veils can be formed on preform reinforcements having a variety of complex shapes. Moreover, spray application of the veil produces similar results to commercially available veil mats, and the cost of application is considerably less than that of using veil mats for the same purpose.

Many modifications to the methods and products of the invention are possible without departing from the spirit of the invention. For example, if a smooth finish is desired on both the interior and exterior surfaces of the final part, the fibers 81 may be coated with a binder as they exit the tube 13, and then applied to the screen 7 for 10 minutes.
Apply to a thickness of ~30 mils (0.0254-0.076 cm). A reinforcing cut strand 2 can be deposited on top of this to the desired reinforcement thickness, after which an outer layer of fibers 81 can be applied to this reinforcing strand. With this method, a part obtained by molding the resulting preform can have smooth surfaces on both the inner and outer surfaces. Although the accompanying drawings show two zones as air impingement zones for breaking the cut strands into filaments, it is possible to use one zone or more than one zone if desired. One thing is clear.

Other variations include the use of other binders as opposed to the use of a binder resin spray applied to the strands as they leave the tube 13, as in embodiments of the present invention. It is also within the scope of this invention to spray apply filaments of powdered resin or thermoplastic resin to reinforcing strands and surface fibers so that these binders melt onto the strands and/or fibers in a heated plenum to consolidate the preform. belongs to

As another variation, although cut strands 2 have been described as providing a reinforcing layer to the preform, a continuous strand or a combination of cut and continuous strands with the addition of a binder may be used with chopping rollers 40. and 41 may be replaced with pull rollers and a device similar to preform machine 20 feeding the continuous strand into hopper 46 and tube 13 may be used to discharge the preform screen. Alternatively, the continuous strands may be arranged manually or robotically in one or two directions rather than in a random arrangement.

Although the present invention has been described above with reference to specific examples and comparative embodiments, the present invention is not limited thereto as long as it is described in the claims.

[0043]

Structural members that can be constructed according to the invention can have any size or shape and are free from corners, edges and complex folds due to the mounting fibers used as the second feed of the invention. It is possible to uniformly coat even the surface of the resin, and to produce a structural member with a smooth, resin-rich surface at a low cost.

[Brief explanation of the drawing]

1 is a side view of a rotary preform machine suitable for carrying out the process of the present invention; FIG.

FIG. 2 is a plan view of a preferred preform screen used to implement the invention in a planar section.

FIG. 3 is a cross-sectional view of the preform screen taken along line III-III in FIG. 2;

4 is an enlarged side view of the fiber placement device of FIG. 1, partially cut away; FIG. This includes the internal fluid supply,
and collisions of supplied strands are shown.

[Explanation of symbols]

2 Cutting strand 7 Preform screen 11 Oven chamber 12 Preform machine 13 tube 15 Resin sprayer 16 Strand (first supply) 17 Strand (first supply) 18 Strand (first supply) 19 Chopper unit 20 Cutting machine 27 Strand (second supply) 28 Strand (second supply) 29 Strand (second supply) 80 Cutting strand 81 Fiber

Claims (31)

[Claims] 1. A method for preparing a fiber-containing reinforcement having a veil mat for use with a reinforcement for reinforcing a polymeric material, comprising a requisite amount of strands and suitable dimensional stability of the reinforcement layer. forming a layer of fibrous strands having a sufficient amount of binder to provide the properties of the reinforcement and the properties of the reinforcement to the polymer being reinforced; and the reinforcement layer by placing individual fibers. forming a layer in contact with; the layer of individual fibers contains more resin than the reinforcement layer, and the reinforcement is used in a polymeric formation to be reinforced; , a method for preparing a fiber-containing reinforcement having a thickness sufficient to provide a smooth surface. 2. The fiber-containing reinforcement comprises fibrous strands on the surface of the preform screen and an amount of binder sufficient to provide adequate dimensional stability and reinforcing properties to the preform. and bonded to each other and to the reinforcing fibers until a requisite amount of the strands are deposited on the surface to form a reinforcement layer of fibrous strands, Multiple fibers formed into discrete lengths from the cut strands are placed over the previously collected reinforcing fibers to form a layer of filamentated fibers that provides a smooth surface to the part molded from the preform. 2. The method of claim 1, wherein the preform is formed by placing. 3. The individual fibers and reinforcing strands are glass fibers and glass strands.
The method according to claim 1. 4. The method of claim 2, wherein the fibrous strands and fibers are glass strands and fibers. 5. A fiber-containing reinforcement having a reinforcement layer consisting of strands prepared according to the method of claim 1 and a surface layer consisting of individual fibers. 6. Individual fibers formed in loosely bonded bundles are placed on a surface, and the reinforcement layer consisting of cut strands is then applied to a thickness sufficient to provide the requisite reinforcing properties. in addition to the layer of individual fibers so as to cover the reinforcement layer with a second layer of individual fibers formed from a compacted bundle of the fibers, 2. The method of claim 1, wherein the layers are bonded by a binder resin which, when heated and partially set, solidifies the layers to form a preform. 7. A fiber reinforcement having an inner surface of individual fibers, a reinforcing layer of cut strands covering the inner surface, and an outer individual fiber surface, the fiber surface and the cut strands covering the inner surface. A fiber reinforcement, wherein the layer of strands is formed by the method of claim 6. 8. A method for preparing a fiber-loaded preform, the method comprising the steps of: providing fibrous strands on the surface of a preform screen and providing suitable shape stability and reinforcement for the preform; applying a binder in an amount sufficient to provide properties until the requisite amount of strands is deposited on the surface; and providing a smooth surface when the preform is later molded into a part; the preparation of a preform in which individual fibers having more resin than the first layer are placed on the surface of the first layer to form a layer of sufficient thickness to provide how to. 9. The method of claim 8, wherein the individual fibers and cut strands are glass fibers and glass strands. 10. The method of claim 8, wherein the fibers and cut strands are glass fibers and strands. 11. A fiber reinforced preform having a reinforcement layer of cut strands and a surface layer of individual fibers prepared according to the method of claim 8. 12. The method of claim 8, including discontinuing the supply of reinforcing strands before the second layer of individual fibers is added. 13. Forming and placing the second layer of individual fibers provides a high velocity fluid to impinge and filamentize the cut strands to extract more resin from the strands. 9. The method of claim 8, comprising forming a layer of fibers comprising: 14. The fibers of the second layer have a diameter ranging from about 1 to about 35 microns and are aqueous-based selected from the group consisting of fiber lubricants, organofunctional silane binders, film-forming polymers, and mixtures thereof. 14. The method of claim 13, having a chemical treatment agent residue, the amount of the residue on the strand ranging from about 0.02 to about 0.5 weight percent based on L0I. 15. A method for preparing a preform for use in molding a structural fluid composite, the method comprising: , placing fibrous strands with applied preform binder resin on the surface of the preform screen until sufficient strands have been deposited, and applying reinforcing fibers from the cut strands to previously collected reinforcing fibers. placing a plurality of fibers formed in discrete lengths to form a filamentary fiber layer that is bonded to each other and to reinforcing fibers and provides a smooth surface to a part molded from the preform; A method for preparing a preform, including: 16. The method of claim 15, wherein the cut strands and fibers are glass strands and fibers. 17. A fiber-reinforced preform prepared according to the method of claim 15, having a reinforcement layer of cut strands and a surface layer of individual fibers. 18. The method of claim 15, including discontinuing the supply of reinforcing strands before said second layer of individual fibers is added. 19. The strand layer and fibers include:
A layer of glass strands and glass fiber,
16. The method according to claim 15. 20. The preform of claim 19, wherein the amount of residue on the continuous strand of fibers is less than 0.1 weight percent based on L0I. 21. Claim 15, wherein said fibers are formed from discrete lengths of fibers having the same diameter as the fibers in the strands forming said reinforcement layer.
The method described in. 22. The method of claim 21, wherein the fibers and cut strands are glass fibers and glass strands. 23. The method of claim 15, wherein the individual fibers are comprised of single thread rovings and the reinforcing strands are comprised of multiple thread rovings. 24. The method of claim 23, wherein said fibers and said cut strands are glass fibers and glass strands. 25. The preform of claim 23, wherein the layer of cut strands and the surface layer of fibers are formed from cut glass strands and cut glass fibers. 26. The method of claim 15, wherein said individual fibers are formed from individual lengths of strands comprising fibers having a larger diameter than the fibers forming a reinforcing strand layer of said preform. 27. The method of claim 15, wherein the strand layer and fibers are glass strand layers and glass fibers. 28. The layer of cut strands and the surface layer of fibers are formed from cut glass strands and cut glass fibers, wherein the fibers have an L0I of from about 0.02 to 28. The preform of claim 27, having a sizing with an amount of residue on the continuous strand of fibers in the range of about 0.5 weight percent. 29. A method of forming a fiber-loaded preform, the method comprising: feeding individual fibers formed from loosely compacted bundles of fibers onto a screen surface to form a single fiber-loaded preform; forming a layer of strands, adding a layer of strands to the individual fiber layer of sufficient thickness to provide the requisite preform reinforcement properties, and adding the reinforcing layer to the consolidated layer of the fiber. covering with a second layer of individual fibers formed from the bundle, all of which are bonded by a binder resin that, when heated and partially set, causes the layer to harden to form a preform. A method of forming a preform. 30. The method of claim 29, wherein the layer of strands added to the individual fiber layer is formed from cut strands. 31. A fiber reinforced preform having an inner discrete fiber surface, a cut strand reinforcement layer covering the inner surface, and an outer discrete fiber surface, the fiber surface and the cut strand layer comprising: A fiber reinforced preform formed by the method of claim 29.