JP2021011094A - Molded body, composite molded body, and method for producing composite molded body - Google Patents

Abstract

To provide: a first molded body that has a groove shape and through which a composite molded body capable of achieving both joining strength and airtightness at a high level can be obtained; a composite molded body capable of achieving both joining strength and airtightness at a high level; and a method for producing the composite molded body.SOLUTION: The purpose of the present invention is accomplished by a first grooved resin molded body including a fibrous filler and having a groove which is for joining a second resin by injection molding and is provided through the irradiation of laser light, in which the groove has: (A) a joining strength securing part in which a projection area ratio of a region crossing, within a range of 90° ±60°, with respect to an orientation direction of the fibrous filler of the first resin molded body is 60% or higher with respect to a projection area ratio of the entire groove; and (B) an airtightness securing part crossing a path from one end to another end, which requires airtightness, in the joining part with a second molded body, the airtightness securing part crossing the path in a direction that cuts off the path.SELECTED DRAWING: Figure 1

Description

The present invention relates to a molded product, a composite molded product, and a method for producing a composite molded product.

In recent years, in fields such as automobiles, electric products, and industrial equipment, there has been a growing movement to replace metal molded bodies with resin molded bodies in order to meet demands for reduction of carbon dioxide emissions and reduction of manufacturing costs. Along with this, it is required to provide a technique for firmly integrating one resin molded body with another resin molded body, a metal molded body, or the like.

Patent Document 1 discloses a method of manufacturing a composite molded product by integrating one resin molded product and another molded product. In this method, a part of the resin is removed from a resin molded product containing a fibrous inorganic filler to form a groove in which the inorganic filler is exposed from the side surface to obtain a grooved resin molded product, and then grooved. The grooved surface of the resin molded product is used as a contact surface to be integrated with other molded products. When obtaining a grooved resin molded product, partial removal of the resin is performed by laser irradiation. According to this method, the inorganic filler exposed in the groove acts as an anchor for suppressing the destruction of the grooved resin molded article and other molded articles, and as a result, the strength of the composite molded article can be significantly increased.

Further, in Patent Document 2, when forming a groove in the first molded body, the groove is a concave portion and the gap between the grooves is a convex portion, and the shape of the groove such as the convex portion or the concave portion in the direction in which the fluid of the second resin is injected. By specifying the above, a technique for improving the bonding strength of the composite molded body has been proposed.

Japanese Patent No. 2015-91642 Japanese Patent No. 6368681

In the composite molded body using such a grooved first molded body, the joint strength could be significantly improved, but when not only the joint strength but also the airtightness is required, the joint strength can be improved. Therefore, it may be difficult to achieve both of them due to the dilemma that an air leak path is generated through the groove by providing many grooves.

The present invention has been made to solve the above problems, and an object of the present invention is to have a groove shape capable of obtaining a composite molded body having both joint strength and airtightness at a high level. It is an object of the present invention to provide a molded product, a composite molded product capable of achieving both joint strength and airtightness at a high level, and a method for producing the composite molded product.

The present inventors have solved the above problems by the following.

1. 1. A grooved first resin molded product containing a fibrous filler and having a groove provided by irradiation with laser light for joining the second resin by injection molding, wherein the groove is (A) the first. 1 The joint strength securing portion in which the ratio of the projected area of the region intersecting within 90 ° ± 60 ° with respect to the orientation direction of the fibrous filler of the resin molded product is 60% or more with respect to the projected area of the entire groove, and , (B) At the joint portion of the second resin with the molded product, there is an airtightness ensuring portion that intersects the path from one end to the other end in the edge cutting direction, which requires airtightness. , Grooved first resin molded product.
2. 2. The grooved first resin molded product according to 1 above, wherein the joint strength securing portion (A) has one or more structures selected from linear, striped, grid-like, wavy, dendritic, and fish bone-like. ..
3. 3. The grooved first resin molded product according to 1 or 2 above, wherein the groove width of the (A) bonding strength securing portion is 80% or less of the average fiber length of the fibrous filler.
4. (B) The airtightness ensuring portion has one or more structures selected from linear, circumferential, concentric, and contour lines along the end of the joint surface that requires airtightness. The grooved first molded body described in Crab.
5. A composite molded body of a grooved first resin molded body and a second resin molded body containing a fibrous filler and having grooves provided by irradiation with laser light, wherein the grooves are (A) said. A joint strength securing portion, wherein the ratio of the projected area of the region intersecting within 90 ° ± 45 ° with respect to the orientation direction of the fibrous filler of the first resin molded product is 60% or more with respect to the projected area of the entire groove. (B) The joint with the second resin molded product has an airtightness ensuring portion that intersects the path from one end to the other end, which requires airtightness, in the direction of edge cutting. , Composite molded body.
6. A method of injecting a second resin into a first resin molded product containing a fibrous filler to produce a composite molded product, wherein the first resin molded product containing the fibrous filler is (A) a first resin molded product. The ratio of the projected area of the region intersecting within 90 ° ± 45 ° with respect to the orientation direction of the fibrous filler is 60% or more of the projected area of the entire groove, and the joint strength securing portion and (B) No. 2 At the joint with the resin molded body, a groove having an airtightness ensuring portion that intersects the path from one end to the other end, which requires airtightness, in the direction of edge cutting is formed by laser light. The process of forming by irradiation,
A method for producing a composite molded body, comprising: (A) a step of injection molding a second resin into a first resin molded body having a groove having a joint strength securing portion and (B) an airtightness ensuring portion.

According to the present invention, it is possible to solve the problem of generating an air leak path by a groove for improving the joint strength, and to achieve both the joint strength and the airtightness at a high level.

It is a schematic diagram which shows the 1st resin molded article which concerns on this embodiment. It is a schematic diagram which shows the orientation direction of a fibrous filler in a lattice-shaped groove and the angle (θ1, θ2) formed by the groove. It is a schematic diagram which shows the groove pattern example (a) of the 1st resin molded article which concerns on this embodiment. It is a schematic diagram which shows the groove pattern example (b) of the 1st resin molded article which concerns on this embodiment. It is a schematic schematic diagram (a) which shows the manufacturing process of the test piece of an Example. It is a schematic schematic diagram (b) which shows the manufacturing process of the test piece of an Example. It is a schematic schematic diagram (c) which shows the manufacturing process of the test piece of an Example. It is a schematic diagram which shows the test piece which forms the concentric groove and the groove of the oblique lattice of 45 ° with respect to the orientation direction of the fibrous filler, which is an example. It is a schematic diagram which shows the test piece which forms the concentric groove and the striped groove of 90 ° with respect to the orientation direction of a fibrous filler which becomes an Example. It is a schematic diagram which shows the test piece which forms only the concentric groove which becomes a comparative example. It is a schematic diagram which shows the test piece which forms only the groove of the oblique lattice of 45 ° with respect to the orientation direction of the fibrous filler which is a comparative example. FIG. 5 is a schematic view showing a test piece forming a concentric groove and a striped groove at 0 ° with respect to the orientation direction of the fibrous filler, which is a comparative example. It is a figure which shows the airtightness tester E used in an Example.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be carried out with appropriate modifications within the scope of the object of the present invention. .. In addition, although the description may be omitted as appropriate for the parts where the description is duplicated, the gist of the invention is not limited.

<First resin molded product>
As the first resin molded product, a resin molded product containing a fibrous filler can be used.
The fibrous filler is not particularly limited, and known fibrous fillers such as glass fibers (chopped strands, long fibers, flat cross-sectional fibers, etc.), carbon fibers, whisker fibers, metal fibers, etc. can be used. Among these, in order to efficiently form a groove in the resin molded body by the laser light described later, it is preferable that the fibrous filler transmits the laser light, and it is particularly preferable to use the glass fiber. ..

The resin constituting the first resin molded product is not particularly limited, but it is preferable to use a thermoplastic resin that can be easily processed by injection molding in terms of orienting the fibrous filler in the molded product. Examples of suitable resins include polyacetal (POM), polyamide (PA), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycarbonate (PC), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), and styrene resins. , Acrylic resin and the like. In addition, in order to efficiently form a groove in the resin molded product by the laser light described later, the resin molded product may contain a compound (coloring agent or the like) that absorbs the laser light.

FIG. 1 shows (A) a groove 3 of a joint strength securing portion and (B) a groove 4 of an airtightness ensuring portion of the first resin molded body 1 according to the embodiment of the present invention. Reference numeral 2 in FIG. 1 is a fibrous filler contained in the first resin molded product, and the grooves 3 have a diagonal lattice shape intersecting at 45 ° with respect to the orientation direction thereof. Further, since the groove 3 is formed with a width of about 70% of the fiber length of the fibrous filler, the fibrous filler 2 bridges the side wall portion of the groove 3 without falling off. Alternatively, it exists in a state of protruding from the side wall portion.

As a result, when the second resin is molded, the second resin that has entered the groove 3 wraps around and holds the fibrous filler 2, so that a high anchoring effect can be exhibited and sufficient bonding strength can be obtained. .. The angle formed by the orientation direction of the groove 3 and the fibrous filler 2 for suppressing the falling off of the fibrous filler 2 and obtaining the anchoring effect with the second resin should intersect within 90 ° ± 45 °. It is formed.

The angle is preferably 90 ° ± 40 ° or less, more preferably 90 ° ± 35 ° or less, and particularly preferably 90 ° ± 30 ° or less. Further, the ratio of the projected area of the region intersecting at the angle to the projected area of the entire groove 3 is 60% or more, preferably 70% or more, more preferably 75% or more, and 80%. It is more preferably% or more.

The orientation direction of the fibrous filler 2 is not always completely aligned in the molded product, and there is usually some variation, but in the present invention, the orientation direction of the fibrous filler 2 is the same as that of the fibrous filler 2. Can be calculated from the average of 100 orientation directions randomly selected from the fibrous filler 2 exposed inside the groove 3 of the joint strength securing portion, which is difficult due to the small amount of the fibrous filler 2. In this case, the flow direction of the resin in the joint strength securing portion when molding the first resin molded body may be regarded as the orientation direction of the fibrous filler 2.

The groove 3 may be formed in a pattern such as a straight line, a striped shape, a lattice shape, a wavy line shape, a dendritic shape, or a fish bone shape, but when the orientation direction of the fibrous filler 2 varies. Considering the above, lattice-like (oblique lattice-like), wavy, dendritic, and fish bone-like are preferable, and from the viewpoint of ease of processing and versatility for design, lattice-like (oblique lattice-like), when molding the second resin. From the viewpoint of efficiently discharging the air in the groove, it is preferable that the shape is dendritic or fish bone. Further, the width of the groove 3 is preferably formed at 80% or less of the fiber length of the fibrous filler 2, more preferably 75% or less, and further preferably 70% or less. ..

Here, in a pattern in which the grooves 3 are in a grid pattern (oblique grid pattern), as shown in FIG. 2, the grooves arranged in a certain direction are at an angle (θ1) within 90 ° ± 45 ° with the orientation direction of the fibrous filler 2. ), The grooves arranged in other directions forming the lattice may inevitably have an angle (θ2) that does not correspond to within 90 ° ± 45 °, in which case the angle within 90 ° ± 45 °. The rate of crossing at may be less than 60%.

In such a case, θ2 may be ignored and θ1 may satisfy the above ratio. Further, when the groove 3 has a curved pattern such as a wavy line, the angle formed by the tangent line at the position where the groove 3 intersects the orientation direction of the fibrous filler 2 and the orientation direction satisfies the above ratio. It should be.

Further, the groove 4 of the airtightness ensuring portion (B) in FIG. 1 has a contour line that intersects the path 5 that requires airtightness in the direction of edge cutting. The width of the groove 4 is also 70% of the fiber length of the fibrous filler 2 like the groove 3. The width of the groove 4 may be appropriately set in consideration of the creepage distance for ensuring the necessary airtightness regardless of the fiber length of the fibrous filler 2, but it is complicated to change the setting of the laser irradiation device. In consideration of this, it is usually sufficient to set according to the groove 3. Usually, the width of the groove is preferably 10 to 1000 μm and the depth is preferably 10 to 1000 μm.

The grooves 4 are linear, wavy, stripped, circumferential, concentric, along the edges of the joint surface that requires airtightness, so as to intersect the path 5 that requires airtightness in the cutting direction. It may be formed in a pattern such as a contour line. The arrangement of the groove 4 and the groove 3 is not particularly limited, but the groove 4 is preferably provided at the outer edge of the joint region in order to surely cut off the start point or the end point of the path 5. There may be a plurality of (A) joint strength securing portions and (B) airtightness ensuring portions.

It should be noted that, as shown in FIG. 3, patterns such as a grid pattern and a fish bone pattern mentioned as the pattern of the groove 3 are arranged in the form described as the pattern of the groove 4 such as a contour line as shown in FIG. , Path 5 may be trimmed.

As the cross-sectional shape of the groove, a generally known shape can be appropriately selected, and it is preferably rectangular, trapezoidal, V-shaped, U-shaped, arc, or the like.

<Manufacturing method of grooved first resin molded product>
The method of forming the groove of the first resin molded product of the present invention is performed by irradiating the planned joining region of the first resin molded product with a laser beam. By decomposing and sublimating the resin with a laser to form a groove, it is possible to form a fine groove in an arbitrary region without the need for complicated mold preparation. If it can be confirmed by Raman spectroscopic analysis of the groove surface of the first resin molded body that the carbonized layer of the resin is present, it can be determined that the resin is formed by laser irradiation.

<Composite molded body>
The composite molded product of the present invention can be produced by binding the second resin molded product to the first resin molded product. The bond to the first resin molded body can be manufactured by injection molding the second resin constituting the second resin molded body on the first resin molded body.

The resin constituting the second resin molded product is thermoplastic or thermosetting. The first resin constituting the first resin molded product and the second resin constituting the second resin molded product may be the same or different. Both the first resin molded product and the second resin molded product may be resin molded products containing a fibrous inorganic filler, and other known additives (antioxidants, stabilizers, ultraviolet absorbers, lubricants, release agents). It may be a resin molded product containing a mold agent, a plasticizer, a colorant, a reinforcing material, a toughness improving agent, a fluidity improving agent, a hydrolysis resistance improving agent, etc.).

<Manufacturing method of composite molded product>
First, the first resin constituting the first resin molded body is melted and injection-molded by a mold forming a desired shape. At this time, the mold may be provided with irregularities to form a groove separately from the one by the laser. After that, a desired groove is formed on the surface of the first resin molded product that is bonded to the second resin molded product by irradiation with laser light. Next, a grooved first resin molded body having a groove formed therein is placed in a mold, and a second resin constituting the second resin molded body is flowed therein for injection molding. For injection molding onto the first resin molded body, normal conditions can be appropriately selected.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

As shown in FIG. 5, a polyphenylene sulfide resin containing 40% by mass of glass fiber (Durafide (registered trademark) 1140A1 manufactured by Polyplastics Co., Ltd.) was used as the first resin molded product, and the cylinder temperature was 320 ° C., gold. A resin plate of 80 mm x 80 mm x 3 mm is manufactured by injection molding from a side gate of width 6 mm x thickness 3 mm provided in the center of one side at a mold temperature of 140 ° C., an injection speed of 30 mm / sec, and a holding pressure of 60 MPa. Then, as shown in FIG. 6, a disk-shaped test piece having a diameter of 50 mm was cut out from the central portion, and then a disc-shaped test piece 6 having a diameter of 20 mm was cut out from the central portion 6 was prepared. Next, as shown in the hatched portion of FIG. 7, a sample 101 having various patterns of grooves, which will be described later, was prepared by laser irradiation with a region having a diameter of 20 mm to 30 mm from the center of the disk having the hole as a planned joining region. did.

<Groove formation>
Using the laser marker MD-V9900 (manufactured by KEYENCE, laser type: YV04 laser, transmission wavelength: 1064 nm, maximum rated output: 13 W (average)), the first resin has an output of 90%, a frequency of 40 kHz, and a scanning speed of 1000 mm / s. Grooves of various patterns as shown in FIGS. 4 to 11 were formed in the planned joining region of the molded body. The depth and width of the grooves and the spacing between the grooves were all adjusted to be 100 μm.

In Example 1 shown in FIG. 8, contour lines (concentric circles) having a width of 100 μm are formed twice at 100 μm intervals from a position offset by 100 μm from the inner edge, and the outer edge is 100 μm wide with an interval of 100 μm. Diagonal grid-like grooves are formed at intervals of 100 μm. Here, the orientation direction of the fibrous filler is the vertical direction of the paper surface, and both θ1 and θ2 are 45 °.

In Example 2 shown in FIG. 9, contour lines (concentric circles) having a width of 100 μm are formed twice at 100 μm intervals from a position offset by 100 μm from the inner edge, and the outer edge is 100 μm wide with an interval of 100 μm. Striped grooves are formed in the left-right direction of the paper surface at intervals of 100 μm. Here, the orientation direction of the fibrous filler is the vertical direction of the paper surface, and the angle formed by the groove is 90 °.

In Comparative Example 1 shown in FIG. 10, contour lines (concentric circles) having a width of 100 μm are formed five times at intervals of 100 μm from a position offset by 100 μm from the inner edge. Here, the orientation direction of the fibrous filler is the vertical direction of the paper surface, and the angle formed by the groove is 90 ° at the upper and lower ends of the circumference of the paper surface, but 0 ° at the left and right ends of the circumference, 90 °. The proportion of grooves that intersect within ± 45 ° is 50%. In the case of Comparative Example 1, it can be said that the pattern does not have the joint strength securing portion, but the above ratio is calculated by considering that the airtightness ensuring portion also functions as the joint strength securing portion.

In Comparative Example 2 shown in FIG. 11, diagonal grid-like grooves having a width of 100 μm and intervals of 100 μm are formed from the inner edge to the outer edge. Here, the orientation direction of the fibrous filler is the vertical direction of the paper surface, and both θ1 and θ2 are 45 °.

In Comparative Example 3 shown in FIG. 12, contour lines (concentric circles) having a width of 100 μm are formed twice at 100 μm intervals from a position offset by 100 μm from the inner edge, and then separated by 100 μm to reach the outer edge with a width of 100 μm. Striped grooves are formed in the vertical direction of the paper surface at intervals of 100 μm. Here, the orientation direction of the fibrous filler is the vertical direction of the paper surface, and the angle formed by the groove is 0 °.

Next, as shown in FIG. 7, the second resin was injection-molded into a disk shape having a diameter of 30 mm and a thickness of 1 mm so as to be in contact with the planned joining region of the first resin molded body 101 of each Example and Comparative Example. The second resin molded product 102 was formed to obtain composite molded products (101 and 102). The second resin is a polybutylene terephthalate resin containing 30% by mass of glass fiber (Duranex (registered trademark) 3300 manufactured by Polyplastics Co., Ltd.), a cylinder temperature of 270 ° C, a mold temperature of 80 ° C, and an injection speed of 30 mm / Filling was performed from a pin gate having a diameter of 1 mm provided at the center of the surface opposite to the joint surface at sec and a holding pressure of 60 MPa.

<Evaluation>
The composite molded body produced by the above method was subjected to an air leak test by the following method. FIG. 13 is a vertical cross-sectional view showing a method of airtightness evaluation using the airtightness tester E. The airtightness tester E includes an airtightness tester main body 106 and an airtightness tester lid 103. The composite molded body was attached to the airtightness tester main body 106 via the O-ring 105, and the lower part of the composite molded body was sealed. Then, the airtightness tester lid 103 was placed on the first resin molded body 101 of the composite molded body and clamped.

Distilled water 104 was poured onto the composite molded body containing the second resin molded body 102, and the portion 102 of the second resin molded body of the composite molded body was completely immersed in the distilled water 104. Air was blown through the line 107, a pressure of 0.2 MPa was applied to the inside 106 of the main body of the airtightness tester until a leak occurred, and the leak of air bubbles was visually observed.

<Result>
In Examples 1 and 2, the second resin molded product broke before the leak. In Comparative Examples 1 and 3, the interface between the first resin molded product and the second resin molded product was peeled off due to insufficient bonding strength. In Comparative Example 2, a leak occurred from the interface between the first resin molded product and the second resin molded product. From the above, it was confirmed that according to the present invention, both high bonding strength and airtightness can be achieved.

1 1st resin molded body 2 Fibrous filler 3 (A) Groove of joint strength securing part 4 (B) Groove of airtightness securing part 5 Route required to secure airtightness

(A) Joint strength securing part (B) Airtightness securing part

101 1st resin molded body 102 2nd resin molded body 103 Airtightness tester lid 104 Distilled water 105 O-ring 106 Airtightness tester body 107 Pressurization line 108 Pressure

Claims (6)

A grooved first resin molded product containing a fibrous filler and having a groove provided by irradiation with laser light for joining the second resin by injection molding, wherein the groove is (A) the first. 1 The joint strength securing portion and the joint strength securing portion in which the ratio of the projected area of the region intersecting within 90 ° ± 60 ° with respect to the orientation direction of the fibrous filler of the resin molded product is 60% or more with respect to the projected area of the entire groove. , (B) At the joint portion of the second resin with the molded product, there is an airtightness ensuring portion that intersects the path from one end to the other end in the edge cutting direction, which requires airtightness. , Grooved first resin molded product. The grooved first resin molding according to claim 1, wherein the joint strength securing portion (A) has one or more structures selected from linear, striped, grid-like, wavy, dendritic, and fish bone-like. body. The grooved first resin molded product according to claim 1 or 2, wherein the groove width of the (A) bonding strength securing portion is 80% or less of the average fiber length of the fibrous filler. Claims 1 to 3 that the airtightness ensuring portion (B) has one or more structures selected from a linear shape, a circumferential shape along an end portion of a joint surface that requires airtightness, a concentric shape, and a contour line shape. The grooved first molded body according to any one. A composite molded body of a grooved first resin molded body and a second resin molded body containing a fibrous filler and having grooves provided by irradiation with laser light, wherein the grooves are (A) said. A joint strength securing portion, wherein the ratio of the projected area of the region intersecting within 90 ° ± 45 ° with respect to the orientation direction of the fibrous filler of the first resin molded product is 60% or more with respect to the projected area of the entire groove. (B) The joint with the second resin molded product has an airtightness ensuring portion that intersects the path from one end to the other end, which requires airtightness, in the direction of edge cutting. , Composite molded body. A method of injecting a second resin into a first resin molded product containing a fibrous filler to produce a composite molded product, wherein the first resin molded product containing the fibrous filler is (A) a first resin molded product. The ratio of the projected area of the region intersecting within 90 ° ± 45 ° with respect to the orientation direction of the fibrous filler is 60% or more of the projected area of the entire groove, and the joint strength securing portion and (B) No. 2 At the joint with the resin molded body, a groove having an airtightness ensuring portion that intersects the path from one end to the other end, which requires airtightness, in the direction of edge cutting is formed by laser light. The process of forming by irradiation,
A method for producing a composite molded body, comprising: (A) a step of injection molding a second resin into a first resin molded body having a groove having a joint strength securing portion and (B) an airtightness ensuring portion.

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