JPH0579484B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a sheet-like resin composite material for molding consisting of a resin and a fiber base material. More specifically, it includes glass fiber base materials such as chopped strands, pine, and cloth, carbon fiber base materials, natural fibers such as cotton and linen, and synthetic fibers such as polyester, polyamide, and polyvinyl alcohol. Regarding the method of producing a sheet-like resin composite material for molding by impregnating one or more selected types of fiber base materials such as organic fiber base materials with a liquid resin or a resin mixture, in particular, these fiber base materials The present invention relates to a technique for promoting impregnation of resin into a fiber base material and defoaming in the process of laminating a mixture of a release sheet and a resin on one side of a release sheet, and then winding the laminate into a roll with the laminate inside, for example. The purpose is to provide a high-quality, high-performance molding material for resin/fiber composite products (hereinafter referred to as FRP), that is, prepreg, which has a high content of fiber base material and has no or little bubbles and whitening.

[Conventional technology]

Conventionally, SMC was used as a sheet-shaped FRP molding material.
(sheet molding compound) is known.
For example, there are rubber belt type and mesh belt type machines for this production, and in the former, a laminate of liquid resin and fiber base material sandwiched between two release films is placed on a flat rubber belt. By pressing the laminate with a plurality of flat rolls or striped rolls along the mesh belt, forces such as compression, shearing, and stretching are applied to the laminate to promote impregnation. is added to further promote impregnation. Incidentally, since SMC generally contains powder/granular filler at a high concentration in addition to liquid resin and fibers, the viscosity of the mixture of liquid resin and filler during impregnation is quite high, for example, 100 poise or more. In order to prevent the resin from flowing out due to the above-mentioned compression force necessary to impregnate the fiber base material with this highly viscous system, release films are essential on both sides.

On the other hand, as a manufacturing method for sheet-like FRP molded products,
There is a continuous forming method for FRP corrugated sheets. This product is SMC
Unlike the above, the viscosity of the liquid resin system is low because it does not contain powder or granular filler or contains only a small amount of it. For this reason, the impregnation method using the pressure of various pressure rolls used in SMC has to be limited to a range that does not increase the flow of the resin, which greatly limits its use, so alternative impregnation and defoaming methods As a result, complex techniques are required, such as the method of laminating resin and fibers, the installation of special defoaming equipment, and the development of additives and fiber treatment agents that improve the wetting of the resin to the fiber base material.

[Problem that the invention seeks to solve]

1 to 1 at working temperature to the technical problem targeted by the present invention.
A liquid resin or resin mixture having a relatively low viscosity of 50 poise is applied to chopped strands,
This is a method for impregnating a fiber base material in the form of mat or cloth in a short period of time. More specifically, after the liquid resin and fiber base material are laminated on a release sheet that moves in one direction at a constant speed, the laminate is rolled up on a roll, that is, for a limited distance. and complete the impregnation within the time,
The aim is to propose conditions or devices that completely expel air or bubbles that tend to remain at the interface between fibers and resin.

It is known that when a porous solid is impregnated with a liquid, the amount of liquid impregnated within a certain period of time is qualitatively expressed by the following empirical formula.

W∝T・t/η×ω where W is the weight of the impregnated liquid, T is the temperature, and t
is the time the liquid is in contact with the solid, η is the viscosity of the liquid,
ω is the work done during impregnation, and what this equation means is that in a system of homogeneous liquid and solid combinations, the temperature is high, the contact time is long, the viscosity is as low as possible, and special It is equally common experience in the industry to increase the amount of impregnation using equipment that provides a good amount of impregnation work. This work includes, for example, squeezing rolls in the impregnating tank, flat rolls called impregnating rolls, various striped rolls, or nip rolls,
It is also known that it consists of ``squeezing'', ``kneading'', ``pressing'', ``pulling'', etc. performed mechanically using a squeeze roll or the like.

As mentioned above, the reason why conventional SMC manufacturing machines accomplish the impregnation work using forces such as compression and shearing using a relatively simple mechanism of a series of pressure rolls and belts is because the material system has a high viscosity and This is done by sandwiching both sides with release films. On the other hand, in the case of a system with a low viscosity such as in the case of corrugated sheet molding, a special coater is used to immerse the fibers in the liquid resin, and a presser is used to keep the fibers immersed in the liquid resin for a long time. Impregnation and defoaming are carried out by devising jigs, etc., and by using a special vacuum suction device that removes air remaining in the laminate of fiber base material and resin.

[Means for solving problems]

In view of the prior art as described above, the present inventors
As a result of intensive research into the impregnation and defoaming of relatively low-viscosity liquid resin into fiber base materials, we have found that continuous equipment for sheet-form molding materials can be made extremely easily by installing a new accessory device. The inventors have discovered that the desired objective can be achieved, and have arrived at the present invention.

That is, the method for manufacturing a sheet-like resin composite material for molding according to the present invention is a method for manufacturing a sheet-like resin composite material for molding by impregnating a fiber base material with a liquid resin. A fiber base material and a liquid resin are laminated on top of the laminate, and a plurality of cylindrical rotating rolls with many needle-like protrusions on the surface are pressed while rotating.
Impregnation, defoaming and leveling of sheet molding material by pressing the roll or rolls with a flat surface and/or grooves to such an extent that a bank of liquid resin is formed in front of the rolls. It is characterized by promoting.

[Effect]

The principle on which the present invention is based utilizes the aforementioned factors such as "squeezing" and "massaging" that have been conventionally used for impregnation work, but these factors are done in such a way that no wide-range liquid flow occurs. It means having work done locally. In the case of mixing low-viscosity liquids, considering that "stirring" is one of the best tasks, it can be said to provide local stirring. From this point of view, for example
Various presser rolls used in SMC manufacturing machines are:
Either method is unsuitable because it tends to cause the liquid to flow over a wide range, especially in a direction perpendicular to the direction of movement of the sheet. In other words, in a device in which pressure acts on a surface or a band, a wide range of flow occurs along the contact surface.

The shape of the external surface of the jig that localizes the pressure can be ``isolated protrusions,'' and either a large number of these protrusions attached to a plane and moved periodically, or a jig with many protrusions on the surface. Either of rotating and moving individual rolls can be put to practical use.
Among these methods, the latter roll method is mechanically simple and effective in the continuous production method of sheet-like materials, which is the object of the present invention. Even if the roll is fixed, the roll rotates as the sheet moves, but if the roll is further reciprocated in the direction of sheet movement, the frequency of pressing by the roll can be increased.

As a result of further investigation into the shape of the "protrusion," the present inventors found that the tip of the protrusion that is necessary for the protrusion to push into the laminate of liquid resin and fiber base material, that is, the tip of the protrusion as the roll rotates. It has been found that thinner protrusions and a greater number are more effective for impregnation, as long as they have the necessary stiffness to easily reach the bottom of the laminate container. However, in order to prevent breakage of the release sheet, the rigidity and hardness of the protrusions should not be too high, and the material used should be organic monofilament,
Among them, it has been found that pig hair and single plastic fibers such as nylon are suitable. The shape of the protrusions effective for impregnation has a suitable range depending on the degree of pressing as well as the viscosity, fiber base material content, thickness, etc. of the composite laminate.

In order to make the pressure effective, increase the number of protrusions,
Moreover, in order to localize the pressure, it is better that the protrusions be thin and have a large number of protrusions. The length of the protrusion is at least twice the thickness of the laminate, and the thickness is standard from the tip to the base, but is not limited to this. There is also no particular restriction on the shape of the tip. The standard direction of the protrusion from the surface of the cylindrical base is perpendicular to the surface, but this is not a limitation.

A feature of the present invention is that a flat roll and/or a sinew roll is used in conjunction with the above-mentioned rotating roll with projections. Although the laminate is highly impregnated using a roll with protrusions, in systems with high viscosity, surface leveling was not always completely completed. For this reason, I thought of combining the widely used flat rolls and sinew rolls,
As a result of the study, it was found that it is easy to complete the leveling by using flat rolls or striped rolls, and what is more noteworthy is that by creating a bank of liquid resin in front of the roll by pressing, it is possible to eliminate the protrusions. It has been found that even the portions left unimpregnated by the tamping roll are completely impregnated. Regarding the conditions for bank formation, if the bank is too large,
The degree of pressure is limited because the liquid flows perpendicular to the direction of sheet travel, that is, along the contact line of the rolls. A sinew roll with parallel grooves, the depth of which is not more than three times the thickness of the laminate, i.e. a sinew roll with circumferential grooves with a standard depth of 1 to 4 mm is suitable. be. There is no limit to the outer diameter or groove pitch of these rolls. Therefore, the optimum conditions for promotion of impregnation and leveling by bank formation can be selected from an appropriate number of flat rolls and striped rolls and the degree of pressing of each.

The present invention will be described in detail below.The manufacturing apparatus that characterizes the present invention is specified as follows. First, regarding rolls with protrusions, the outer diameter and shape of the protrusions - length and thickness - depend on the type, thickness, viscosity and mixing ratio of the composite laminate.
The standard length is 3 to 30 mm, although the density and preferred specifications of the material differ.
Rod-shaped needle-like protrusions with a diameter of 0.1 to 3 mm and a length-to-diameter ratio of 5 to 1.00 are attached radially in a dense manner on the surface of a cylinder with a diameter of 10 to 50 mm. It has a shape that allows it to rotate freely around the cylindrical core. The number of protrusions is not particularly limited, but is preferably in the range of 10 to 500 protrusions/cm ² . In order to press the laminate downward with this roll with protrusions, it is preferable to fix the roll through a small compressor. In addition, it is preferable to arrange a plurality of rolls along the direction of movement of the sheet to sequentially impregnate the laminate. Furthermore, at this time, it is possible to prevent the impregnation effect from decreasing due to the fiber base material being wrapped around the rolls. Therefore, it is convenient to arrange rolls with large outer diameters on the upstream side of sheet movement. Furthermore, if the frame of the device to which these rolls are fixed is given reciprocating motion in the direction of movement of the sheet, the frequency of rotation will increase accordingly, which is effective.

One or more flat rolls and/or sinusoidal rolls installed downstream of the protruding roll are connected and fixed so as to obtain pressure in the same manner as the protruding roll. These rolls bring out the effect of the bank, but in order to prevent the liquid from flowing too much in the lateral direction due to the bank and to achieve leveling, the flat rolls are used to adjust the pressure and also to prevent the liquid from flowing in the horizontal direction. It is preferable that the roll has grooves parallel to the outer periphery and the depth of the grooves is within three times that of the laminate, typically 1 to 4 mm. The greater the number of these rolls, the more effective they are, but when used in combination with rolls with protrusions to increase the degree of impregnation as a whole and to create a smoother device, the number of rolls with protrusions is at most 1/5 to 1/3 of the roll with protrusions. Combinations of numbers are valid.

After the impregnation process and leveling have been completed, the sheet-like molding material is continuously rolled up using a conventional device or cut into a regular length with the release sheet facing outside.

If you use a release sheet with release treatment on both sides, you can roll it up as it is,
Furthermore, even when stacked, the molding material is easily peeled off during use, which is convenient.

The resin that is the main component of the FRP molding material that is the object of the present invention is a thermosetting oligomer and its reactive diluent solution, and the viscosity of the mixture of these and the additives other than the fiber base material described below is The liquid is at most 50 poise, preferably 20 poise or less. Suitable examples include unsaturated polyester resin, vinyl ester resin, epoxy resin, aryl resin,
Alternatively, it is a thermosetting oligomer classified as a phenol resin, etc., and a solution obtained by diluting these with a reactive low-molecular organic compound, and further includes a curing reaction catalyst, a curing reaction accelerator, and, if necessary, a viscosity modifier and a wetting agent. , inorganic fillers, etc. are added. More specifically, in the case of unsaturated polyester resins or vinyl ester resins, the respective base oligomers or solutions obtained by diluting these with reactive unsaturated compounds such as styrene, diallyl phthalate, and acrylic esters. If the purpose is heat curing, an appropriate amount of an organic peroxide catalyst is added, and if the purpose is ultraviolet curing, an appropriate amount of photosensitizer is added, and if necessary, a thickener such as magnesium oxide or polyisocyanate is added. , etc. and mix. The viscosity of the mixture is suitably below 50 poise under working conditions, preferably from 1 to 20 poise.

As the fiber base material, neither the material nor the form is specified; chopped strands of glass fiber, carbon fiber, and organic fibers such as polyester, polyamide, polyvinyl alcohol, and cellulose, which are widely used in FRP, are used as fiber base materials. Alternatively, short fibers, mats made from them, long fiber mats, and various cloths are used.

The method of laminating the liquid resin and the fiber base material is not particularly limited, and various coating techniques can be applied. Among these methods, if the fiber base material is cloth or long-fiber pine, an impregnating coating method is used in which the fiber is passed through a liquid resin bath, or more generally, a liquid resin is applied to a certain thickness on a release paper using a knife coater, etc. A method is used in which fiber base materials are laminated on top of each other.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Unsaturated polyester resin (Rigorac M411,
(manufactured by Showa Kobunshi), 4 parts of polystyrene (S-Brite #8, manufactured by Showa Denko) as a low shrinkage agent per 100 parts of resin, and t-butyl perbenzoate (Perbutyl Z, manufactured by NOF) as a curing catalyst.
1.2 parts, 2 parts of magnesium oxide (Magmitsuku, manufactured by Kyowa Chemical Industries) as a thickener, 2 parts of zinc stearate as a mold release agent, 10 parts of calcium carbonate (Softon 1200, manufactured by Bihoku Chemical), and an appropriate amount of styrene. Monomers were blended, and this blend was mixed in a Henschel mixer and then transferred to a vacuum tank for preliminary defoaming to prepare a liquid resin mixture having a viscosity (B-type viscometer) of 18 poise at room temperature.

It has a flat section with an effective width of 600 mm and an effective length of 2,500 mm on which rolls for impregnation can be installed between the raw material supply section and the sheet winding section. We created a machine with a drive mechanism that can move the release sheet at a constant speed. In a cylinder with an outer diameter of 25 mm, pig hair with a diameter of about 0.2 mm is densely planted perpendicular to the cylinder surface, and the diameter to the tip of the pig hair is
4 rolls with circular protrusions that are 35mm, then the outer diameter
Four circular rolls with an outer diameter of 25 mm made of 15 mm cylinders with pig hair attached in the same way, and 30 mm outer diameter with a depth of 2
Two steel strip rolls with mm-thick grooves parallel to their circumferences were arranged sequentially from upstream to downstream, and each of these rolls was fixed to the frame of the machine via a spring. The width of each of these rolls is approximately 450
It was warm in mm.

A knife coater was installed in the raw material supply section, and the width was set to 400 mm, and the clearance between the knife blade and the release sheet was set to approximately 1 mm. A mat unwinding machine is installed above this, and chopped strand mat is laminated on top of the resin mixture coated on the release sheet with a knife coater to a constant thickness. Asahi fiberglass CM305 (width 500 mm) was used as the chopped strand mat, and Fujimori Kogyo's Binasheet 80×T (width 500 mm) was used as the release sheet.

The pressure of the roll was adjusted by the degree of tightening of the spring. This pressure is based on the size of the bank of resin liquid formed in front of each roll, and the pressure is applied until just before this bank occurs for a roll with 8 protrusions, and until a fairly high bank is formed for a striped roll. And so. The moving speed of the sheet was 2 m/min. Under these conditions, when the laminate passes the second or third protruded roll from the upstream,
The resin completely penetrated to the top of the glass pine.

The sheet-like laminate that had completed the pressing process with these rolls was wound up into a paper tube with the release sheet facing outside. Roll the sheet around 10m each into a paper tube,
This was wrapped in kraft paper laminated with aluminum foil on the inside, and both ends were tied with rubber bands to prevent the styrene monomer in the material from scattering. This product was stored in an air tank kept at a temperature of 40℃ for 2 days to mature and thicken. After being taken out and cooled to room temperature, it was cut into strips using a commercially available slitter (a machine whose roll surface has been treated with release properties). 100mm and 150mm tape,
It was wrapped around a paper tube core of the same width and stored and sealed in a cylindrical tin can.

The sheet-like composite material product obtained as this tape had a thickness of about 0.8 mm, was flexible and had considerable adhesiveness. Almost no residual air bubbles were observed in the material.

Comparative Example 1 A manufacturing test was conducted using the same raw materials and manufacturing conditions as in Example 1, except that the various rolls installed in the sheet-like unsaturated polyester resin composite manufacturing apparatus of Example 1 were replaced with the following rolls.

The rolls used were, in order from upstream, flat rolls (outer diameter 50 mm), two rolls, and sinew rolls (outer diameter 50 mm, depth 2).
There are 3 rolls (with parallel grooves of mm diameter) and 4 striped rolls (with parallel grooves of 30 mm outer diameter and 2 mm depth), and the degree of pressure of each roll is such that the two most downstream rolls form a bank. Others were on the verge of being able to bank.

After the manufactured sheet material had thickened, before being slit, it was cut in parallel by approximately 100 mm while being stacked on a release sheet, and the state of the remaining air bubbles was observed.
Considerable air bubbles were observed.

Application example 1 From the sheet-like product with a width of 150 mm obtained in Example 1,
Cut 5 sheets of 150 x 150 mm ² , remove the release sheet, overlap them, and press them with a 50 ton compression molding machine at a temperature of 160°C for 2 minutes to form a 200 mm square board with a thickness of about 2 mm. did.

No residual bubbles or whitening were observed on this board.

Application example 2 After scraping the outer surface of an iron pipe with a length of 1000 mm and an outer diameter of 70 mm, clean it and place the 100 mm wide sheet material obtained in Example 1 on top of it, peeling off the release sheet and cutting one end 20 mm in length. They were overlapped and wrapped diagonally, and then pressed with the palm of the hand through a release sheet to bring the pipe surface and the sheet-like material into close contact, so that no air remained between them. This product was placed in an air constant temperature bath maintained at a temperature of 160 to 165°C for 3 minutes, and then taken out.

The FRP layer wrapped around the outside of the pipe was hard with a barcol hardness (934-1 type, hereinafter the same) of 58, and no residual bubbles or whitening were observed.

Example 2 Vinyl ester resin (Epivis type epoxy acrylate resin: Lipoxy R802, manufactured by Showa Kobunshi)
Mix 7.2 parts of phthalic anhydride to 100 parts,
The reaction was carried out at ~110°C for 90 minutes. This modified vinyl ester resin (liquid mixed with about 45% styrene) 100
In part, photosensitizer, 2-hydroxy-2-methyl-
Adding 1 part of 1-phenylpropanone (Darukiyure 1173, manufactured by Merck) and 1 part of magnesium oxide (Magmic, manufactured by Kyowa Chemical Industry) as a thickener,
This mixture was stirred and mixed under reduced pressure using an intensive mixer. The viscosity of this liquid resin mixture was 15 poise.

A sheet-like composite material was produced using the same machine and method as in Example 1, and after 2 days of thickening, a tape-like product with a width of 100 mm was obtained using a slitter. The product was a flexible sheet approximately 0.7 mm thick and highly adhesive. Almost no air bubbles remained in this product.

Application example 3: Clean the top surface of a 3 mm thick flat iron plate (approximately 100 x 100 mm ² ) with red rust visible in some areas by scrubbing it.
On top of this, 2-hydroxy-2-methyl-1 was added to the vinyl ester resin (Lipoxy R802) of Example 2.
- Brush a solution containing 1% phenylpropanone as a primer, and then apply Example 2 on top of that as a primer.
The sheet-like material manufactured by was cut into 100 mm square pieces, pasted together, and crimped.

Commercially available light irradiation equipment (sunlight, SSL-250A,
A 100 V (manufactured by Stanley Electric) was turned on and irradiated vertically from 10 cm above the surface of the sheet material. Curing progresses with the irradiation time, and after 10 minutes, the FRP layer has a Barcol hardness of 51 and an adhesion strength of 50 kg/kg in a peel test using an adhesion tester (Elcometer).
Cohesive failure occurred in ^cm2 . Almost no air bubbles were observed in the FRP layer.

Comparative Example 2 A sheet-shaped vinyl ester resin composite material was manufactured using the same raw materials as in Example 2 and using the same manufacturing equipment and conditions as in Comparative Example 1. After thickening this material, slit it to a width of 100mm, and then
A square sheet was cut out and cured by irradiation with light in the same manner as in Application Example 3. After 10 minutes, scattered white areas were observed in the cured FRP product.

Application Example 4 The vinyl ester resin composite tape (width 100 mm) obtained in Example 2 was wrapped around an iron pipe in the same manner as in Application Example 2. This object was held horizontally on a stand at a height of about 500 mm and exposed to sunlight (location: Isesaki City, Gunma Prefecture, date and time: May, 2:00 p.m., weather: clear).
An aluminum plate was placed under the pedestal so that sunlight reflected and hit the back side of the pipe. After 20 minutes, the back side
The FRP layer was also almost cured. Visual inspection of the entire surface of the FRP layer revealed no whitening or residual bubbles.

〔Effect of the invention〕

The sheet-shaped resin composite material for molding according to the method of the present invention can be rolled or pasted on the outside or inside of a structure or molded object made of metal, concrete, or plastic, and then cured to form an FRP surface layer. Alternatively, since the FRP lining layer can be easily formed, it can provide a new and useful method for the manufacturing of composite pipes and the construction of reinforced and corrosion-resistant FRP linings for buildings and structures. It also provides a useful process for easily and high-quality manufacturing of various FRP molded products using various medium-high pressure molding methods as prepreg.

In particular, it is possible to minimize air bubbles even during no-pressure or low-pressure molding, including wrapping and pasting, thereby providing molded products with excellent mechanical and electrical strength, as well as water resistance, corrosion resistance, and weather resistance. There is practical value of the molding material of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the manufacturing process of a sheet-like resin composite material for molding used in an example of the present invention, and FIGS. 2 and 3 are explanatory diagrams each showing a roll with protrusions of the present invention. be. 1... Chopped strand mat, 2... Double-sided release sheet, 3... Knife coater, 4... Product winding machine, 5, 5'... Presser roll attachment part,
6... Roll with protrusions, 7... Flat roll or striped roll, 8... Liquid resin, 10... Protrusions.

Claims (1)

[Claims] 1. A method for producing a sheet-like resin composite material for molding by impregnating a fiber base material with a liquid resin, in which the fiber base material and the liquid resin are laminated on a release sheet that moves at a constant speed. A plurality of cylindrical rotary rolls with many needle-like protrusions on the surface are pressed while rotating from above this laminate, and one or more rolls with a flat surface and/or A sheet-shaped resin for molding, characterized in that impregnation, defoaming, and leveling of a sheet-shaped molding material are promoted by pressing with a grooved roll to such an extent that a bank of liquid resin is formed in front of the roll. Method of manufacturing composite materials. 2 As a cylindrical rotating roll with many needle-like protrusions on the surface, a cylindrical surface with a diameter of 10 to 50 mm and a length of 3
~30mm, diameter 0.1~3mm, length to diameter ratio 5
A patent characterized by using a rotating body that has a rod-shaped or needle-shaped protrusion with a diameter of ~100 mm, has an outer diameter of 30 to 100 mm to the tip of the protrusion, and can freely rotate around the central axis of the cylinder. A method for manufacturing a sheet-shaped resin composite material for molding according to claim 1.