JPH09254182A - Reactive injection molded object of norbornene type monomer having rib - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a rib hard to generate the crack caused by voids to enhance the strength of the rib by providing a rib molded so that the ridgeline thereof is depressed to the inside with respect to the straight line connecting a first rising point and a second rising point. SOLUTION: A flange 4 is integrally molded at a part of a reactive injection molded object 2 of a norbornene type monomer and a rib 10 is integrally molded at the crossing part of the first surface 6 being the outer surface of the flange 4 and the second surface 8 being the outer surface of the molded object 2. The ridgeline 12 being the line connecting the apex of the rib 10 is formed within the plane almost vertical to the first and second surfaces 6, 8 and has a shape depressed inside the straight line bb' connecting the first rising point (b) being the crossing point of the first surface 6 and the ridgeline 12 and the second rising point b' being the crossing point of the second surface 8 and the ridgeline 12. By this constitution, even if external force acts on the part of the flange 4, the possibility of the damage of said part is reduced because of the reinforcing effect by the rib 10.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a reaction injection molded body of a norbornene-based monomer having ribs.

[0002]

2. Description of the Related Art Concrete molded products and metal molded products have disadvantages such as heavy weight and difficulty in cutting, and in recent years, molded products conventionally formed of metal or concrete have been made of synthetic resin. There are many attempts to mold.

In particular, a reaction injection molded article (RIM) of a norbornene-based monomer has been studied for use in various technical fields because of its excellent impact resistance and easy molding of a large molded article. . RIM like this
In the case of a molded body, a flange is provided on the member formed of the RIM molded body when molding a particularly large assembly or when a member formed of the RIM molded body is attached to another member.
The flange may be attached to other members with bolts and nuts or adhesives.

In that case, the strength of the flange may become a problem. For example, when transferring a RIM molded body having a flange, the molded body may be pulled up by using the flange portion. At that time, depending on the weight of the molded body, the flange portion may be cracked. was there.

In order to solve these problems, it has been considered to provide a simple triangular rib at the base of the flange to reinforce the flange.

[0006]

However, with this conventional simple triangular rib, voids may occur in the rib portion of the molded body after RIM molding, and this may cause the rib to break. Further, if there are voids, the appearance of the molded product becomes poor and the quality of the molded product deteriorates.

The present invention has been made in view of the above circumstances, and a reaction injection molded product of a norbornene-based monomer having a high-quality rib having a high-strength and a clean appearance, which is unlikely to be cracked by a void in the rib. The purpose is to provide.

[0008]

In order to achieve the above object, a reaction injection molded body of a norbornene-based monomer having a rib according to the present invention is a point of intersection of a ridgeline of the rib and a first surface of the molded body. One of the rising points and a second rising point which is an intersection of the ridgeline of the rib and the second surface of the molded body are formed so that the ridgeline of the rib is recessed inward. . The thickness of the molded body on which the ribs are formed is preferably 2 mm or more, more preferably 2.5 mm or more, and particularly preferably 3 mm or more. If it is too thin, the molded product may not have sufficient strength. Also,
The upper limit of the thickness of the molded body is preferably 30 mm or less, more preferably 20 mm or less, and particularly preferably 15 mm or less. If it is too thick, it becomes difficult to manufacture a molded body having ribs.

Usually, the first surface and the second surface of the molded body on which the ribs are formed are preferably flat surfaces, but they may be curved surfaces. The portion where the first surface and the second surface contact each other is preferably a curved surface. This is to improve the moldability. The ridgeline of the rib according to the present invention (the line connecting the vertices of the rib in the vertical cross section of the rib) has a shape in which at least two straight lines intersect or a curved shape in order to form a shape that is recessed inward. . When the ridge line of the rib is formed in a shape in which straight lines intersect, it is preferable to connect the intersecting portions of the straight lines with curved lines. Further, it is preferable that the ridgeline near the first rising point, which is the intersection of the ridgeline and the first surface, is a smooth curve. The same applies to the ridgeline near the second rising point. This is to improve the moldability. In the present invention, the longitudinal section of the rib is a surface that is substantially perpendicular to both the first surface and the second surface and that passes through the ridgeline of the rib.

The cross-sectional shape of the rib is preferably mountain-shaped. It is preferable that the top of the mountain has a convex curved shape and the skirt of the mountain has a concave curved shape. The cross section of the rib is a cross section of the rib cut along a plane perpendicular to the longitudinal (longitudinal) direction of the rib and perpendicular to the first surface or the second surface.

Since the molded product having ribs according to the present invention is formed by a reaction injection molded product of a norbornene-based monomer, it has excellent impact resistance. Further, by forming the rib according to the present invention on the flange portion of the molded body, the strength of that portion is improved, and even if an external force acts on the flange portion, that portion is less likely to be damaged.

Further, in the present invention, by forming the rib as described above, cracks due to voids are less likely to occur,
High-quality ribs having high strength and a clean appearance can be formed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a reaction injection-molded product of a norbornene-based monomer having ribs according to the present invention will be described in detail based on an embodiment shown in the drawings. First Embodiment FIG. 1 is a schematic view showing a vertical cross-sectional dimensional relationship of a rib of a reaction injection molded body of a norbornene-based monomer according to an embodiment of the present invention, and FIG. 2 is a perspective view of the rib.

As shown in FIGS. 1 and 2, in this embodiment,
Part of the reaction injection molded body 2 of norbornene-based monomer,
The flange 4 is integrally molded, and the rib 10 is integrally molded at the intersection of the first surface 6 that is the outer surface of the flange 4 and the second surface 8 that is the outer surface of the molded body 2.

A ridge line 12 which is a line connecting the vertices of the rib 10.
1 and 2 are formed so as to be included in a surface that is substantially perpendicular to the first surface 6 and the second surface 8, as shown in FIGS. In the present embodiment, the ridge line 12 is substantially composed of two straight lines bd and b′d. The ridge line 12 is the first surface 6
And the ridgeline 12 at the first rising point b and the second
The shape is recessed inward of a straight line bb ′ connecting the second rising point b ′ that is the intersection of the surface 8 and the ridge line 12.

Thickness t _{1 of the} molded body 2 on which the rib 10 is formed
Is preferably 2 mm or more, more preferably 2.5 mm or more, and particularly preferably 3 mm or more. If it is too thin, the molded body 2 may not have sufficient strength. Further, the upper limit of the thickness of the molded body is preferably 30 mm or less, more preferably 20 mm or less, and particularly preferably 15 mm or less. If it is too thick, it becomes difficult to manufacture a molded body having ribs. It is preferable that t ₂ is thicker than the thickness t ₁ . For example, t
₂ = t ₁ +2 mm is preferred.

In FIG. 1, for convenience of illustration, the intersection a of the first surface 6 and the second surface 8 is angular, but in an actual molded body, as shown in FIG. 3, it is rounded. It is preferable. Also, two straight lines b forming the ridgeline 12 of the rib 10
The intersection d of d and b′d is shown as being square in FIG. 1 for convenience of illustration, but in an actual molded body, it is preferable to have a concave curve as shown in FIG. The ridgeline near the first rising point b, which is the intersection of the ridgeline 12 and the first surface 6, is preferably a smooth curve, as shown in FIG. The same applies to the ridge line 12 near the second rising point b ′ shown in FIG. This is to improve the moldability.

In the present embodiment, as shown in FIG. 1, the intersection point d from the intersection point d of the two straight lines bd and b'd forming the ridgeline 12 of the rib 10 and the perpendicular line drawn to the first surface 6 is designated as c, Let c ′ be the intersection with the perpendicular drawn from the intersection d to the second surface 8,
Let e be the intersection with the perpendicular drawn from the intersection d to the straight line bb ', and f be the intersection with the perpendicular drawn from the intersection a to the straight bb'.
And In addition, the length of the straight line ac is l, the length of the straight line ab is L, the length of the straight line ac 'is l', and the straight line ab 'is
When the length of L is L ′, the following relationships are preferable.

That is, L / l and L '/ l' are preferably 1.5 or more, more preferably 2 or more, and particularly preferably 2.5 or more. These L / l and L '
The upper limit of / l 'is preferably 10 or less, more preferably 8 or less, and particularly preferably 7 or less. If these values are too small, the reinforcing effect of the rib 10 is small, and voids are likely to occur. If it is too large, the rib does not have a sufficient reinforcing effect.

Further, h / H (recess ratio of intersection d) is preferably 0.20 or more, more preferably 0.30 or more,
Particularly preferably, it is 0.40 or more. This upper limit is preferably 0.90 or less, more preferably 0.85 or less,
It is particularly preferably 0.80 or less. If this value is too small, the rib does not have a sufficient reinforcing effect, and if it is too large, voids may occur and the material is wasted.

Further, as shown in FIG. 2, the width W of the flange is
In such a case, L / W is preferably 0.1 or more, more preferably 0.2 or more, and particularly preferably 0.3 or more. This upper limit is preferably 0.9 or less, more preferably 0.7 or less, and particularly preferably 0.5 or less. If this value is too small, the rib does not have a sufficient reinforcing effect, and if too large, it interferes with the mounting of the bolts and nuts and wastes the material.

In this embodiment, the cross section of the rib 10 is preferably mountain-shaped as shown in FIG.
It is preferable that the peak of the mountain has a convex curved shape and the skirt of the mountain has a concave curved shape as shown in FIG. In addition,
The transverse section of the rib 10 is a section obtained by cutting the rib 10 along a plane perpendicular to the longitudinal (longitudinal) direction of the rib 10 and perpendicular to the first surface 6 or the second surface 8. In FIG. 5, the apex of the chevron rib 10 intersects the ridge line 12.

In the cross section of the rib 10, the width t ₃ of the hem of the rib 10 is defined as the rising points g on both sides of the hem of the rib 10.
(See FIG. 5) The distance between the ribs 10 is defined as the rib width T ₄ at the midpoint of the perpendicular line hx drawn from the apex of the rib 10 to the first surface 6 or the second surface 8. Define. In the present embodiment, it is preferable that the following relationships hold.

That is, t ₄ / t ₃ is preferably 0.
52 or more, more preferably 0.54 or more, and particularly preferably 0.55 or more. Also, the upper limit of t ₄ / t ₃ is
It is preferably 0.80 or less, more preferably 0.75 or less, and particularly preferably 0.70 or less. If this value is too small, voids are likely to occur near the ridgeline 12 of the rib, and if this value is too large, voids are likely to occur near the hem of the rib.

In the rib 10 of the reaction injection molded body of the norbornene-based monomer according to this embodiment, it is preferable that the corner portion of the molded body 2 including the flange 4 and the rib 10 has an appropriate radius of curvature. For example, in the corners,
The radius of curvature is preferably 0.5 mm or more, more preferably 1
It is preferable to have a radius of curvature of mm or more, particularly preferably 2 mm or more. That is, the inner surface of the mold for molding the molded body 2 preferably has a radius of 0.5 m.
It is desirable that the sphere having a diameter of m, more preferably 1 mm, and particularly preferably 2 mm is rolled so that there is no portion that does not contact the sphere. This is because if there is such a portion where the balls do not come into contact with each other, it is difficult to fill the molding material and a void may be generated in the molded body.

The molded body 2 having the flange 4 and the rib 10 of this embodiment is made of a polynorbornene resin obtained by a reaction injection molding method (RIM). In particular, those composed of a ring-opened polymer of a norbornene-based monomer modified with an elastomer are preferable.

Examples of the elastomer include polybutadiene, styrene-butadiene copolymer (SBR), styrene-butadiene-styrene block copolymer (SB).
S), polyisoprene, styrene-isoprene-styrene block copolymer (SIS), ethylene-propylene-diene terpolymer (EPT) and the like.

The blending ratio of the elastomer is 1 to 20 parts by weight, preferably 2 to 15 parts by weight, based on 100 parts by weight of the norbornene-based monomer. When the blending ratio of the elastomer is low, the flexibility decreases. Conversely, if the proportion of the elastomer is too large, the glass transition temperature decreases and the strength decreases, which is not preferable.

The monomer is a cycloolefin having a norbornene ring such as dicyclopentadiene, dihydrodicyclopentadiene, tetracyclododecene and tricyclopentadiene. The metathesis catalyst is not particularly limited as long as it is a known metathesis catalyst for bulk polymerization of norbornene-based monomers such as organic ammonium molybdates such as tungsten hexachloride, tridodecyl ammonium molybdate, and tri (tridecyl) ammonium molybdate. However, organic ammonium molybdate is particularly preferred.

Examples of the activator (cocatalyst) include alkylaluminum halides such as ethylaluminum dichloride and diethylaluminum chloride, alkoxyalkylaluminum halides thereof, and organic tin compounds. As a preparation for reaction injection molding, a reaction injection molding material containing a norbornene-based monomer, a metathesis catalyst, and an activator as a main component is a liquid comprising a norbornene-based monomer and a metathesis catalyst, and the norbornene-based monomer and the activator are used. Separately into two stable liquids and separate liquids. At the time of reaction injection molding, the two liquids are mixed, and then the mixed liquid is injected into the cavity of the mold, and bulk polymerization is performed in the cavity to obtain the molded body 2.

The mold used for the reaction injection molding does not necessarily have to be an expensive mold having high rigidity, and is not limited to a metal mold, and a resin mold or a simple mold can be used. This is because the reaction injection molding of the norbornene-based resin can be performed at a relatively low temperature and a low pressure using a low-viscosity reaction liquid. The inside of the mold is sealed with an inert gas, and the components used for the polymerization reaction are stored under an inert gas atmosphere such as nitrogen gas.
And it is preferable to operate.

The mold temperature is preferably 10 to 150.
C., more preferably 30 to 120.degree. C., still more preferably 50 to 100.degree. Mold pressure is usually 0.1-1
It is in the range of 00 kg / cm ² . The polymerization time may be appropriately selected, but is usually from 30 seconds to 2 hours after the completion of the injection of the reaction solution.
It is 0 minutes, preferably 5 minutes or less.

Since the molded body 2 according to the present invention is made of the polynorbornene resin obtained by the reaction injection molding method, the rib 10 can be easily molded integrally, and the relatively large molded body 2 can be molded easily. can do. Further, the polynorbornene-based resin can have a sufficient pressure resistance required for the molded body 2 by utilizing the material characteristic that the specific rigidity is low but the specific strength is high.

In the reaction injection-molded body 2 of norbornene-based monomer having the flange according to this embodiment, due to the reinforcing effect of the rib 10, even if an external force acts on the flange 4, the portion may be damaged. Few. Therefore, even if an external force acts on the flange 6 when the molded body 2 is conveyed, the flange 6 is not damaged.

Further, in this embodiment, since the rib 10 has the above-described shape, cracks due to voids are unlikely to occur in the rib 10, and high-quality ribs having high strength and a clean appearance are formed. can do. Further, since the mating surface 20 (see FIG. 2) of the flange 4 becomes smooth by molding the rib 10 on the flange 4, the mating surface 20 of the flange 4 is brought into contact with another member to separate the molded body 2 from another. At the time of joining to the member of (1), the sealing property of the flange 4 portion is also satisfactorily maintained.

Second Embodiment In the present embodiment, as shown in FIG. 6, the ridgeline 12a of the rib 10a is substantially composed of three or more straight lines. The other configurations of the present embodiment are the same as those of the first embodiment, and have the same effects.

In the present invention, the ridgelines of the ribs may all be concave curves. Third Embodiment In this embodiment, a casing for a septic tank is manufactured by assembling molded bodies 2a to 2f having ribs 10 and flanges 4 similar to the molded body 2 having the ribs 10 and flanges 4 of the first embodiment. It is an example. Other ribs 30 may be formed on any of the molded bodies 2a to 2f, if necessary. By constructing the casings of the septic tank by assembling the molded bodies 2a to 2f having the ribs 10 of this embodiment, a relatively large septic tank excellent in pressure resistance can be manufactured very easily.

The present invention is not limited to the above-mentioned embodiment, but can be variously modified within the scope of the present invention.

[0039]

EXAMPLES The present invention will be described below based on more specific examples, but the present invention is not limited to these examples. Example 1 A reaction injection molded body 2 of norbornene-based monomer having ribs 10 and flanges 4 shown in FIGS.

In the reaction injection molding, 85% dicyclopentadiene (DCP) and 15% asymmetrical cyclopentadiene trimer were used, and styrene-isoprene-
Styrene block copolymer (Kraton 1170, manufactured by Shell Co.) was dissolved in 5% and phenolic antioxidant Irganox 1010 (manufactured by Ciba Geigy Co., Ltd.) was dissolved in 2%. Diethyl aluminum chloride (DEAC) was added to the monomer so that the concentration was 40 mmol, n-propanol was 44 mmol, and silicon tetrachloride was 20 mmol (A).
liquid). On the other hand, tri (tridecyl) ammonium molybdate was added to the monomer at a concentration of 10 mmol (Solution B).

The solutions A and B thus prepared were sent to a power mixer with a gear pump so that the volume ratio was 1: 1, and then the mold temperature was 70 ° C. in the mold. C and injection pressure was 2.0 Kg / cm ² or less. The reaction was carried out for 3 minutes in the mold, and a series of these operations was performed in a nitrogen atmosphere.

Then, the molded body was taken out from the mold to obtain a molded body 2 having the ribs 10 shown in FIGS. Figures 1 and 2
2, the thickness t ₁ of the molded body 2 is 5 mm, the thickness t ₂ of the flange 4 is 7 mm, and the width W of the flange (see FIG.
1) is 70 mm, the length L of the rib 10 shown in FIG. 1 on the first surface side is 25 mm, the projected length 1 of the intersection point d on the first surface side is 6 mm, and Rib length L'is 87
mm, the projection length l ′ of the intersection point d on the second surface side was 13 mm, and the recess ratio (h / H) at the intersection point d was 0.68.
Wires were attached to the flanges 4 of the molded body 2 in which the ribs 10 were formed at a pitch of 270 mm, and the entire molded body 2 was caught, but no damage occurred at the flange portion.

Further, when the flanges 4 of the two molded bodies 2 were adhered to each other using a two-component urethane adhesive (Mighty Grip, manufactured by Japan Synthetic Rubber Co., Ltd.), the adhesive strength was about 6
It was 00 kg. In addition, one of the two molded bodies 2 is used as an upper tank and the other is used as a lower tank, and their flanges 4 are bonded to each other using a two-component urethane adhesive (Mighty Grip, manufactured by Japan Synthetic Rubber Co., Ltd.). Furthermore, when bolts and nuts were fixed at 120 mm intervals, a hole was made in the center of the upper tank, water was filled, and the mixture was allowed to stand for 2 weeks. No water leakage was observed. Further, when the bolts and nuts were fixed at 180 mm intervals, no water leak was observed.

Comparative Example 1 A reaction injection molded body of norbornene type monomer having a flange was molded in the same manner as in Example 1 except that the rib was not formed at the base end of the flange. When a wire was attached to four places around the flange of the molded body according to Comparative Example 1 and the entire molded body was caught, the flange was chipped.

When the flanges 6 of the two molded bodies 2 according to this comparative example were bonded to each other with a two-component urethane adhesive (Mighty Grip, manufactured by Japan Synthetic Rubber Co., Ltd.), the adhesive strength was about 400 kg. . Moreover, of the two molded bodies 2 according to the comparative example, one is an upper tank and the other is a lower tank,
The flanges 6 are bonded to each other with a two-component urethane adhesive (Mighty Grip, manufactured by Japan Synthetic Rubber Co., Ltd.),
Furthermore, fix with bolts and nuts at 120 mm intervals,
When a hole was made in the center of the upper tank and the tank was filled with water and left for 2 weeks, no water leakage was observed. However,
When fixed with bolts and nuts at 180 mm intervals, some water leakage was observed on the 5th day.

Comparative Example 2 A molded body similar to that of Example 1 except that triangular ribs having straight-line ridge lines connecting the intersection points b and b'in FIG. 1 are provided instead of the shape shown by the solid line in FIG. Was produced. Voids were observed in each rib portion.

When wires were attached to four places around the flange of the molded body according to Comparative Example 2 and the entire molded body was caught, cracks and chippings were formed in the rib portions.

[0048]

As described above, according to the present invention, the reaction injection molding of the norbornene-based monomer having a high-quality rib having a high-strength, clean appearance, which is unlikely to cause cracks due to voids in the rib, etc. The body can be provided.

[Brief description of drawings]

FIG. 1 is a schematic view showing a vertical cross-sectional dimensional relationship of ribs of a reaction injection molded body of a norbornene-based monomer according to an embodiment of the present invention.

FIG. 2 is a perspective view of the rib shown in FIG.

FIG. 3 is a schematic view showing details of a rising portion and an intersecting portion of a ridgeline of a rib.

FIG. 4 is a schematic view showing a cross section of a rib.

FIG. 5 is a schematic view showing details of a skirt portion of a rib in a cross section of the rib.

FIG. 6 is a schematic view showing a ridgeline of a rib according to another embodiment of the present invention.

FIG. 7 is a perspective view in which a casing of a septic tank is assembled using a molded body having a rib according to the present invention.

[Explanation of symbols]

 2 ... Molded body 4 ... Flange 6 ... 1st surface 8 ... 2nd surface 10 ... Rib 12 ... Ridge line

Claims (1)

[Claims] 1. A reaction injection molded product of a norbornene-based monomer having a rib integrally formed in a portion where the first surface and the second surface are in contact with each other, the intersection of the ridgeline of the rib and the first surface. And a rib formed so that the ridgeline of the rib is recessed inward with respect to a straight line connecting the first risepoint that is the second risepoint that is the intersection of the ridgeline of the rib and the second surface. Reaction injection molded product of norbornene-based monomer.