JP2017194389A - Evaluation method for resin impregnation of resin molding glass fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation method for resin impregnation of a resin molding glass fiber capable of selecting a glass fiber improved in resin impregnation.SOLUTION: An evaluation method includes: a step for placing a glass fiber 4 on a substrate 3 of which the lightness value is 0 or higher and 70 or lower, and imaging the glass fiber 4 and the substrate 3; an area calculation step for a region corresponding to the glass fiber 4 in an image obtained by imaging in the imaging step; an over-time imaging step for supplying a resin composition 5 to the glass fiber 4 and imaging the resin composition 5 and the glass fiber 4 to which the resin composition is supplied at the same position with the lapse of time; an over-time calculation step for comparing lightness values in a region corresponding to the substrate 3 and a region corresponding to the glass fiber 4 after the resin composition 5 is supplied, in the image obtained by imaging in the imaging step with the lapse of time and calculating an area of a wet-out region in which a difference between the lightness values becomes smaller than a predetermined value that is equal to or smaller than 30, with the lapse of time; and a step for calculating an area ratio of an area of the wet-out region with respect to an area of the region corresponding to the glass fiber 4 with the lapse of time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for evaluating resin impregnation properties of glass fibers for resin molded products.

  Conventionally, it is known to manufacture a resin molded product using SMC (Sheet Molding Compounds) formed by mixing a thermosetting resin composition and glass fiber into a sheet shape. And since the resin molded product from SMC has designability and intensity | strength, it is widely used for a bathtub, a washstand, a kitchen counter, etc.

  For example, as shown in FIG. 4, the SMC is manufactured by mixing a chopped strand obtained by cutting a glass roving 41 into an appropriate length with a resin composition and semi-curing it to a B-stage state. ing. Here, the glass roving 41 is made of a bundle of a plurality of glass fibers called a glass strand 42 having a certain length or more, and the glass strand 42 is a single glass monofilament that is a minimum unit. 43 is formed by binding with a binder 44.

  In the resin molded product from SMC containing such glass fiber, the strength as a composite material is obtained by bonding the cured resin composition and the glass fiber. However, since the resin molded article has appropriate strength and excellent surface aesthetics, the glass fiber has excellent resin impregnation properties, and the glass fiber is impregnated with an appropriate amount of the resin composition. Is required.

  It has been attempted to evaluate the impregnation property of the resin into such glass fibers by various viewpoints and methods.

  For example, a method for evaluating the resin impregnation property of glass fiber by observing voids in the region where the resin impregnation property of the glass fiber is reduced has been proposed for the prepreg in the region of the printed wiring board (patent) Reference 1).

  In the method for evaluating the resin impregnation property of glass fiber described in Patent Document 1, a prepreg is disposed between a light source and a camera, light is irradiated from below the prepreg by the light source, and transmitted light transmitted through the prepreg is captured by the camera. Take an image with. Then, the obtained image is binarized, and the presence / absence and position of voids can be specified based on the data indicating the bright and dark areas on the prepreg surface. That is, in the evaluation method described above, in the portion where there is no void, or in the central portion of the cylindrical void, the light perpendicularly incident on the prepreg travels straight and is displayed brightly, but in the surface portion of the void, The light perpendicularly incident on the prepreg from the light source is refracted and scattered and displayed dark. Such an image is binarized to calculate a void area. If the total area is smaller than a predetermined threshold value, it is determined that the resin impregnation property of the glass fiber is good.

  However, voids become a problem in the prepreg as described above because it causes a decrease in electrical insulation, and detection of voids and evaluation of resin impregnation into glass fibers are not necessarily directly related. There wasn't. In the prepreg, no consideration has been given to design properties such as strength and aesthetic appearance of the surface after molding and curing, which are important in the production of a resin molded product using SMC.

JP 2006-64531 A

  The present invention has been made in view of the circumstances as described above, and provides a glass fiber excellent in resin impregnation property that can obtain a resin molded product that expresses an appropriate strength and has an excellent surface aesthetics. It is an object of the present invention to provide a method for evaluating resin impregnation properties of glass fibers for resin molded products that can be selected.

  In order to solve the above problems, the present inventor has studied in detail the impregnation step of the resin composition into the glass fiber. Therefore, the first thing to be noted is that a binder that binds glass monofilaments in glass fibers to each other in order for the resin molded product to exhibit appropriate strength and to have an excellent surface aesthetics. It is required that glass resin monofilaments are appropriately impregnated with a resin composition. In the impregnation step, the glass fiber is impregnated with the resin composition and passes between the glass strands, and a wet-through process is performed so that the solvent component in the resin composition binds the monofilaments to each other. Melt the wet out. When glass fibers that are quickly wet out are used, an undispersed glass strand does not remain in the cured resin molded product, and a resin molded product exhibiting an excellent appearance can be obtained. On the other hand, if the wet-out is too early, the solvent component is consumed by the time the resin composition reaches the center of the glass fiber or glass fiber mat, and the glass fiber that has not been wet-out remains, which is said to be unimpregnated. . In a state where unimpregnated glass fibers remain, an appearance defect is caused in which undispersed glass strands are raised on the surface of the resin molded product. Moreover, since the part which the resin composition and glass fiber have not contact | adhered arises, malfunctions, such as not expressing desired intensity | strength generate | occur | produce.

  It is considered that using such a wet-out ratio as an index is effective in evaluating the resin impregnation property of the glass fiber.

  Therefore, the present inventors optically observed changes when the glass fiber binder is dissolved by the solvent component in the resin composition, and quantitatively calculated the area of the wet-out region relative to the total area of the glass fiber. Focusing on the evaluation, the present invention has been completed.

The method for evaluating the resin impregnation property of the glass fiber for a resin molded product of the present invention is a method for evaluating a glass fiber in which a glass monofilament is bonded by a binder, which is used for a resin molded product obtained by molding a resin composition. A step of placing the glass fiber on a substrate having a lightness L value of 0 or more and 70 or less and imaging the glass fiber and the substrate, and the glass fiber in an image obtained by imaging in the imaging step Calculating the area S _{0 of} the region corresponding to the above, and supplying the resin composition or a partial component thereof to the glass fiber, and the glass fiber supplying the resin composition at the same position as the step A step of imaging over time, a region corresponding to the substrate in an image obtained by imaging in the step of imaging over time, and a glass after the resin composition is supplied By comparing the lightness L value of the region corresponding to the cellulose fiber, comprising the steps of: over time calculates an area S ₁ of the wet-out area the difference between the lightness L value becomes smaller than a predetermined value of 30 or less, the glass fibers step over time calculates an area ratio of the area S ₁ of the wet-out area to the area S ₀ of the region corresponding to, and comprising a city.

  According to the method for evaluating the resin impregnation property of the glass fiber for a resin molded product of the present invention, it is possible to select a glass fiber that can obtain a resin molded product that expresses an appropriate strength and has an excellent surface appearance.

It is the schematic which illustrated embodiment of this invention. (A) (b) (c) (d) is the figure which showed a mode that the wet-out of glass fiber advanced. It is a block diagram which shows the process of evaluating the resin impregnation property of glass fiber. It is the schematic which showed the structure of the glass fiber for resin molded products typically.

  Below, the evaluation method of the resin impregnation property of the glass fiber for resin molded products of this invention is demonstrated in detail.

  FIG. 1 shows an example of an image measurement system used in the embodiment of the present invention. This image measurement system includes a camera 1 and an image processing device 2. As the camera 1, a camera using a semiconductor element such as a CCD camera can be used. A computer (electronic computer) can be used as the image processing apparatus 2.

  The glass fiber 4 to be evaluated for resin impregnation is placed on the substrate 3 having a lightness L value of 0 or more and 70 or less.

  As shown in FIG. 4, the glass fiber 4 here is a glass fiber formed by bonding a glass monofilament 43 with a binder 44. In the glass fiber 4, a large number of colorless and transparent glass monofilaments 43 are bound by a binder 44 having low transparency. For this reason, many glass fibers 4 are milky white in appearance until mixed with a resin composition 5 described later.

  The binder 44 is not particularly limited as long as it is a resin that can be dissolved by a solvent component in the resin composition 5 used for manufacturing SMC and its molded product, which will be described later. For example, an acrylic resin, an epoxy resin, a urethane resin, etc. Illustrated. The resin used as the binder 44 may be the same type as the resin that is the main component of the resin composition 5 used in the manufacture of SMC and its molded product, or may be a different type of resin. A resin is preferably considered.

  As the glass fiber 4, a commercially available glass roving for SMC molding, a glass fiber mat, chopped strands, or the like can be suitably used. For example, SMC molding glass roving RS 480-550 (manufactured by Nittobo) suitably used for the manufacture of bathtubs, etc., SMC molding glass roving RS 460 A-782 (manufactured by Nittobo) suitably used for automobile bodies, etc. Etc. are exemplified.

  The substrate 3 is a flat plate on which the glass fiber 4 to be evaluated is placed.

  The color tone of the substrate 3 is not particularly limited as long as the value of the lightness L value is within the above range. For example, in addition to black, gray, red, blue, etc. whose lightness L value is 0 or more and 70 or less A substrate exhibiting the following color tone can also be used, and in particular, a black substrate can be preferably used.

The lightness L value here is an index representing lightness in the L ^* a ^* b ^* color system, and can take a numerical value from 0 to 100. When the lightness L value approaches 0, the lightness decreases and the color tone becomes dark, and when the lightness L value approaches 100, the lightness increases and the color tone becomes bright. If the lightness L value exceeds 70, the color tone of the substrate 3 is too bright, and therefore it is difficult to distinguish the glass fiber 4 that has not been wetted out from the substrate 3 during image analysis to be described later.

  The material of the substrate 3 is not particularly limited as long as the value of the lightness L value is within the above range. For example, a resin plate such as an acrylic plate or a vinyl chloride plate, a metal plate whose surface is coated and the metallic luster is suppressed, etc. In particular, an acrylic plate can be preferably used. When an acrylic plate is used as the substrate 3, it is easy to adjust the color tone as described above, and the substrate 3 having various color tones can be used.

  Evaluation of resin impregnation property can be performed according to the block diagram in the procedures of FIGS. 2 (a), (b), (c), and (d) and the procedure of FIG. 3, for example.

  That is, first, as shown in FIG. 2A, the glass fiber 4 to be evaluated is placed on the surface of the base 3, the surfaces of the base 3 and the glass fiber 4 are covered with a colorless and transparent resin film 6, and the camera 1 is used to image the glass fiber 4 and the substrate 3.

  By covering with the resin film 6, it is possible to suppress the scattering of the glass fiber 4 in a dry state, and after supplying the resin composition 5 described later, the volatilization of the solvent component in the resin composition is suppressed, and the glass fiber. 4 can be reliably impregnated with the resin composition 5, and the wet-out can be performed efficiently.

  The material of the resin film 6 is not particularly limited as long as it is a colorless and transparent resin, and examples thereof include polyethylene terephthalate (PET) resin and vinyl chloride resin.

Next, in the above imaging step, the area S ₀ of the region corresponding to the glass fiber in the image obtained by imaging is calculated.

That is, the image data of the substrate 3 and the glass fiber 4 is input to the image processing apparatus 2 such as a computer, and image analysis is performed. The image data is obtained by arranging milky white glass fibers 4 having a high lightness L value on the upper surface of the substrate 3 having a low lightness L value, so that the lightness L values of the base 3 and the glass fibers 4 are measured. The difference is large, and the bright image portion showing the glass fiber 4 and the dark image portion showing the substrate 3 can be clearly distinguished. The bright image portion and the dark image portion of such image data are identified by the image processing device, and the area of the bright image portion is calculated by the image processing device as the area S ₀ of the region corresponding to the glass fiber 4. To do.

  Thereafter, as in the state of FIG. 1, the resin composition 5 or a component of the resin composition 5 (for example, a solvent) is supplied to the glass fiber 4, and the resin composition 5 is supplied at the same position as in the above process. The glass fiber 4 and the substrate 3 are imaged over time. FIGS. 2B, 2C, and 2D schematically show this temporal imaging. Further, the notations (a), (b), (c), and (d) in FIG. 3 correspond to the above-described stages.

  The main component of the resin composition 5 is not particularly limited as long as it is a resin that is usually used in the production of SMC and its molded product, but for example, thermosetting of unsaturated polyester resin, acrylic resin, epoxy resin, phenol resin, etc. The thing which used the singular resin individually or in combination of 2 or more types is illustrated. A solvent, a sizing agent, and the like can be added to the resin composition 5 as long as the evaluation of the resin impregnation property of the glass fiber 4 is not hindered.

  In addition, when the resin composition 5 is a resin composition in which the degree of coloring is intense or lacks in transparency and is cloudy, the glass fiber that has been wetted out even when the binder 44 of the glass fiber 4 is dissolved in the solvent component Does not become transparent, making it difficult to evaluate resin impregnation properties. In this case, a resin composition mainly composed of the same type of resin as the resin composition actually used for the production of SMC or a molded product thereof, and a colorless and transparent one may be used as the evaluation resin composition.

  Moreover, it is preferably considered that the resin composition 5 supplied to the glass fiber 4 contains styrene as a solvent component. By impregnating the glass fiber 4 with the resin composition 5, the styrene in the resin composition 5 can dissolve the binder 44 contained in the glass fiber 4. In the glass fiber 4, in the wet-out region in which the binder 44 is melted by styrene, the glass fiber 4 changes to almost transparent because the refractive index values are close to those of the resin composition 5 and styrene. For example, the glass fiber generally used for the production of a resin molded product is e-glass, the refractive index is 1.55, and the refractive index of the unsaturated polyester resin is about 1.54 to 1.57. The refractive index of styrene as a solvent component is 1.5339. For this reason, the color of the base | substrate 3 arrange | positioned under the glass fiber 4 comes to be visually recognized from on the glass fiber 4. FIG.

  As shown in FIGS. 2B, 2C, and 2D, the glass fiber 4 wet-out process is performed when the glass fiber 4 in the initial state shown in FIG. 2A is imaged. Images are taken over time using the camera 1 at the same position.

In the step of imaging over time, the brightness L value of the region corresponding to the substrate 3 and the region corresponding to the glass fiber 4 after supplying the resin composition 5 in the image obtained by imaging is compared. , calculates the area S ₁ of the wet-out area difference of the lightness L value is 20 or less over time.

That is, image data of the substrate 3 and the glass fiber 4 in which the wet-out is progressing is input to the image processing apparatus 2 such as a computer, and image analysis is performed. As described above, by impregnating the glass fiber 4 with the resin composition 5, the glass fiber 4 becomes transparent in the glass fiber 4 in the wet-out region where the binder 44 is melted by styrene, and the color of the base 3 is the glass fiber 4. It becomes possible to confirm from above. At this time, the brightness L value of the area corresponding to the base 3 and the area corresponding to the glass fiber 4 after the resin composition 5 is supplied is compared, and the difference in the brightness L value is not more than a predetermined value of 30 or less. If it is preferably 20 or less, it can be determined that the glass fiber 4 has been wet-out. Since the difference in the lightness L value between the region corresponding to the substrate 3 and the region corresponding to the glass fiber 4 after supplying the resin composition 5 is smaller, it is considered that the wet-out is surely occurring. It is preferably considered that the difference in lightness L value is 5 or more and 15 or less. Such comparison of the differences in lightness L value and calculation of the area S ₁ of the wet-out area is performed by the image processing apparatus 2.

Finally, over time to calculate the area ratio of the area S ₁ of the wet-out area to the area S ₀ of the region corresponding to the glass fiber 4.

Wet out area area ratio of the area S ₁ of to the area S ₀ of the region corresponding to the glass fiber 4 (%) is calculated by the following equation.

Then, the area ratio of the area S ₁ of the wet-out area to the area S ₀ of the region corresponding to the glass fiber 4 is a predetermined value, preferably determining the time to be a predetermined value of 100% or less than 75%. Here, the threshold of the area ratio can be arbitrarily set in a range of 75% to 100%. In particular, as shown in FIG. 2D, it is exemplified that the wet-out is determined to be completed when the area ratio reaches 95%. On the other hand, when the impregnation of the glass fiber with the resin composition is less than 75%, unimpregnated glass fibers remain inside the molded product, the appearance of the molded product surface is impaired, and a desired strength is obtained. There is a risk of being lost.

  In the evaluation method of the resin impregnation property of the glass fiber for a resin molded product of the present invention, the area ratio is a predetermined value for each of a plurality of types of glass fibers 4 with different binders 44 attached to the surface of the glass monofilament 42, It is also preferably considered to measure the time to reach 95% and compare the resin impregnation properties of multiple types of glass fibers.

  Here, it is preferable that the time until the area ratio reaches 95% is preferably within the range of the curing time in the manufacturing process of a molded product using SMC. Examples of the curing time include a range of about 5 minutes to 30 minutes. If the impregnation of the resin composition into the glass fiber is completed within the above range, a molded product having a desired strength can be obtained without reducing the productivity of the molded product. On the other hand, if the time until the area ratio reaches 95% exceeds 30 minutes, the productivity of the molded product may be reduced.

  Thus, by comparing the time until the area ratio reaches 95%, for example, glass fibers having high resin impregnation properties and glass fibers having low resin impregnation properties can be evaluated and separated. And when manufacturing the resin molded product with a high request | requirement of intensity | strength, and the resin molded product with a very favorable external appearance, the optimal glass fiber for each performance can be selected.

  FIG. 3 shows a block diagram of a method for evaluating the resin impregnation property of glass fiber. In the process of evaluating the resin impregnation property of glass fiber, not only the calculation of the above area ratio (%) but also the area ratio The time to reach 95% is also calculated.

  The above-described evaluation method of the resin impregnation property of the glass fiber for a resin molded article is desirably performed at a constant temperature because the solubility of the binder 44 of the glass fiber 4 depends on the temperature. As the temperature in this case, for example, a range of 15 ° C. or more and 40 ° C. or less is exemplified, but it is preferably considered that the temperature is particularly about 25 ° C.

Although an Example is shown below, the resin impregnation evaluation method of the glass fiber for resin molded products of this invention is not limited at all by the Example.
(Example)
As the resin composition, an unsaturated polyester resin (M540 manufactured by Showa Denko) was used. As glass fiber, (A) SMC molding glass roving RS 480-550 (manufactured by Nittobo) suitably used in bathtubs, etc. (B) SMC molding glass roving RS 460 A-782 (used in automobile bodies, etc.) Nittobo) was used.

One of the above SMC molding glass rovings cut to 1 inch is placed on a black acrylic plate having a base L value of 42, and the base and glass fibers are covered with a transparent PET resin film. It was. A camera is installed vertically above the glass fiber so that the entire substrate and the entire glass fiber can be photographed. The substrate and the glass fiber covered with the transparent PET resin film are imaged, and the obtained image data is image-processed and initialized. The area S ₀ of the region corresponding to the glass fiber in the state was calculated by a computer. Next, the PET film is temporarily removed, and an unsaturated polyester resin diluted with styrene is supplied onto the glass fiber. The substrate and the glass fiber are quickly covered again with the PET resin film, and imaging is performed at that time as the start time. Thereafter, imaging continued over time. Such time-lapse photography was performed at the same position without moving the position of the camera, the base, and the glass fiber from the initial positions. The resulting image data to image processing, the resin composition is impregnated into the glass fiber was calculated by the area S ₁ of the wet-out area binder is dissolved in the glass fibers computer.

Percent ratio of the area S ₁ of the wet-out area to the area S ₀ of the region corresponding to the glass fiber in the initial state was calculated by the computer, the area S of the region area S ₁ of the wet-out area corresponds to the glass fibers in the initial state _The time when 95% of ₀ was reached was defined as the wetout completion time.

  Table 1 shows the measurement results at a room temperature of 23 ° C. and the resin composition at a liquid temperature of 23 ° C.

From the results of Table 1, the glass roving for SMC molding suitably used in bath manufacturing such (A), the area S ₁ of the wet-out area from the supply of the resin composition after 15 minutes corresponds to the glass fibers in the initial state It reached 95% of the area S ₀ of the region, and it was confirmed that the wet-out was completed. On the other hand, the SMC molding glass roving suitably used in the body of an automobile (B), it reached 95% of the area S ₀ of the region area S ₁ of the wet-out area corresponds to the glass fibers in the initial state, wet out It was confirmed that the time required for completion was 100 minutes after the supply of the resin composition.

  From the above results, it can be seen that glass fibers having a high resin impregnation property and glass fibers having a low resin impregnation property can be separated.

DESCRIPTION OF SYMBOLS 1 Camera 2 Image processing apparatus 3 Base | substrate 4 Glass fiber 41 Glass roving 42 Glass strand 43 Glass monofilament 44 Binder 5 Resin composition 6 Resin film S ₀ Area of area corresponding to glass fiber S ₁ Wet out area

Claims (5)

A method for evaluating a glass fiber in which a glass monofilament is bonded by a binder, which is used for a resin molded product obtained by molding a resin composition,
Placing the glass fiber on a substrate having a lightness L value of 0 to 70 and imaging the glass fiber and the substrate;
Calculating an area S _{0 of} a region corresponding to the glass fiber in an image obtained by imaging in the imaging step;
Supplying the resin composition or a partial component thereof to the glass fiber, and imaging the glass fiber supplied with the resin composition at the same position as the step over time;
The brightness L value of the region corresponding to the substrate in the image obtained by imaging in the step of imaging over time and the region corresponding to the glass fiber after supplying the resin composition is compared, and the brightness L a step of over time calculates an area S ₁ of the wet-out area difference value is smaller than a predetermined value of 30 or less,
Step of calculating the area ratio of the area S ₁ of the wet-out area to the area S ₀ of the region corresponding to the glass fibers over time,
The evaluation method of the resin impregnation property of the glass fiber for resin molded products characterized by including these.   The said area ratio is 75% or more and 100% or less, The evaluation method of the resin impregnation property of the glass fiber for resin molded products of Claim 1 characterized by the above-mentioned.   For each of a plurality of types of glass fibers having different binders attached to the surface of the glass monofilament, the time until the area ratio reaches a predetermined value is measured, and the resin impregnation properties of the plurality of types of glass fibers are compared. The evaluation method of resin impregnation property of the glass fiber for resin molded products of Claim 1 or 2 characterized by the above-mentioned.   The difference in brightness L value between the region corresponding to the substrate and the region corresponding to the glass fiber after the resin composition is supplied is 5 or more and 15 or less. The evaluation method of the resin impregnation property of the glass fiber for resin molded products of one term.   The method for evaluating resin impregnation properties of glass fibers for resin molded articles according to any one of claims 1 to 4, wherein the resin composition contains styrene as a solvent component.

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