JPS6294316A - Preparation of uretane molding - Google Patents

Abstract

PURPOSE:To prevent the damage of reinforcing part which occurs in case of demolding, by molding integrally the silicone resin layer at the part where the reinforcing of moldings is required. CONSTITUTION:One-pack type urethane coating material is coated by spraying 31 on an edge 30 formed between the lower stepped part 28 of fixed core 22 and its side part 26. In this coating material, organic metal compounds such as dibutyl-tin dilaurate, etc. are dispersed as catalyst and cured at molding temperature. Mold closing is conducted by the movable core 24 and slidable core 25 after coating the past state two-pack type silicone on the film in the stage of curing and forming silicone resin layer 32. The mixed solution of isocyanate and polyol reaction solutions is poured and cured, and as a result, the curing speed of two-pack type silicone becomes high due to the catalyst. Thus, silicone resin layer 32 is integrally molded with urethane moldings by curing at the same time or before the urethane moldings. In case of mold opening, the moldings 33 integrally molded with silicone resin layer at under-cut part 29 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing a urethane molded product that facilitates demolding.

(Prior art) In general, in urethane molded products made by reaction injection molding (RIM), the undercut portion is easily elastically deformed, so it is relatively easy to forcefully remove the undercut portion (forcible removal) during demolding. .

However, with high modulus urethane, reinforced urethane, etc., the elongation at break decreases as the rigidity of the molded product increases, making it difficult to forcibly remove the undercut portion from the mold, and forcing the mold out may result in plastic deformation, breakage, etc. .

Conventionally, for urethane molded products such as bumpers made by reaction injection molding, measures have been taken to reduce the undercut portion of the molded product and to provide a slide mechanism in the mold to prevent the undercut portion from being forced out. This creates major constraints on the design of molded products and molds.

(Purpose of the Invention) This invention was made to solve the conventional problems described in -1- above, and by integrally forming a silicone resin layer on the parts of the molded product that require reinforcement, it is possible to The purpose of the present invention is to provide a manufacturing capability test for a urethane molded product that can prevent damage to the reinforcing portion that occurs in the process.

(Structure of the Invention) In order to achieve the above object, the present invention first applies a one-component urethane paint containing an organometallic compound catalyst to the molding surface of the mold corresponding to the part reinforcing the molded product. Thereafter, a two-component silicone whose reaction is promoted by the catalyst described above is applied to this layer. Next, reaction injection molding is performed by mixing and injecting a polyol solution and an isocyanate solution into the cavity of the mold, thereby obtaining a molded product in which a silicone resin layer is integrally formed in the portion to be reinforced.

As a result, the part where the integrally formed silicone resin layer reinforces the molded product has a breaking elongation strength of 1■! j, I'm getting it.

(Example) First, an outline of the vM'i direction V of the urethane molded product will be explained.

Figure 1 shows isocyanate reaction solution A and polyol reaction solution B.
FIG. 1 is a process diagram for producing a two-component urethane molded product by reaction injection molding by mixing the two components. In the figure, isocyanate 1
and Freon 2 are charged into a mixing tank 3a to prepare an isocyanate reaction liquid A, and then this isocyanate reaction liquid A is sent to a chemical tank 5a by a pump 4a.
- The path 9a of the chemical tank 5a is circulated by the pump lOa to stabilize the quality of the isocyanate reaction liquid A, and the isocyanate reaction liquid A is stored at a predetermined temperature.

Similarly, polyol reaction solution B is also stored in a mixing tank 3b including polyol 11, crosslinking agent 12, catalyst 13, and glass fiber M14.
It is prepared by charging and stirring, and is sent to the chemical tank 5b by the pump 4b, and the chemical tank 5b - cylinder 6b - valve device 7 - heat exchanger 8b - chemical tank 5b
The polyol reaction solution B is circulated through the route 9b using the pump 10b, and like the isocyanate reaction solution A, the polyol reaction solution B is stored in a state that matches the reaction conditions. Nitrogen is introduced into the circulation path 9b from the nitrogen pump 15 and maintained in an inert atmosphere.

”-The valve distribution device (mixing head) 7 is shown in Fig. 2 (a).
As shown in FIG. 1, both reaction solutions A and H are injected and shut off by the downward movement of the plunger 16. When injecting, the plunger 16 retreats to one side in the figure. -c,
JR outfit F? 7, the inflows 1117a, 17b are brought into communication, the return paths to the circulation paths 9a, 9b are cut off, and the reaction liquids A and B fed into the valve device 7 are all injected into the cavity 21 of the gold ηI20. and the reaction is carried out.

On the other hand, as shown in FIG. 2(b), the plunger 16 is pushed down by hydraulic oil in the gap to be blocked, and the inlet port 17a is opened.
, 17b are sent through the four parts 18 of the plunger 16 without mixing with each other, and are discharged from the discharge 1.
119a and 19b return to the circulation routes 9a and 9b.

An outline of the mold 20 is shown in FIG. In the figure, 22
is the fixed core attached to the fixed plate 23, -1
- A cavity is formed between the movable core 24 that moves in the downward direction {circle around (2)} and the slide core 25 that moves in the left-right direction H when the mold is clamped.

Next, a method for reinforcing the molded product will be explained with reference to FIG.

First, in FIG. 4(a), there is a
A liquid urethane paint is applied as a mold coat paint using a sprayer 31. This one-component urethane paint has a resin component of urethane elastomer and a viscosity of 12 seconds/FC#4.2.
The curing temperature is 60 to 80°C, for example, dibutyltin dilaurate (hereinafter referred to as DBTDL).
An organometallic compound such as (abbreviated as ) is dispersed as a catalyst, and cures at mold temperature. "2 DBTDL is 0.00 parts by weight per 100 parts by weight of non-volatile components of the paint. It contains 1 to 0.5 parts by weight of O.

Next, paste-like two-component silicone is applied to the urethane coating film formed near the marked corner 30 in the curing process to form a silicone resin layer as shown in FIG. 4(b). form 32. The two-component silicone mentioned above has two ingredients that are alcohol type or two ingredients that are 7-minoxy type, and have a dry-to-touch time (tack-free tie 1.) of 3 to 3.
1O min (20℃, 65%RH), 1 near 70℃+1
~2 minutes. In addition, the elongation at break after curing is 300 to 50.
It is 0%. In addition, the elongation at break of two-component polyurethane is 5
It is as low as 0-200%.

Since the above-mentioned two-component silicone is applied to the urethane coating film which is still in a gel state, that is, a sticky state, it is possible to prevent the occurrence of dripping. Furthermore, r)BTr)L contained in the l-liquid type urethane paint acts as a common catalyst for this paint and the two-liquid silicone, promoting the reaction of the two-liquid silicone.

After forming the silicone resin layer 32 in this manner, the mold is clamped by the movable core 24 and the slide core 25, and the isocyanate reaction liquid A and the polyol reaction liquid B are
A mixed solution of the above is injected into the cavity 21 and cured.

The state is shown in FIG. 4(C).

As mentioned above, the curing speed of two-component silicone is DBTDL.
Because it is accelerated by the catalyst, the silicone resin layer 32 is cured at the same time as or before the urethane molding, and becomes integral with the urethane molding.

Next, when the movable core 24 and the slide core 25 are moved and the mold is opened, a molded product 33 with the silicone resin layer 32 integrally formed on the undercut portion 29 is produced, as shown in FIG. 4(d). can get. - Figure 4(e) shows how the molded product is removed from the mold. As shown in the figure, even if the undercut portion 29 is forcibly demolded, the silicone resin layer 3
2 has a large elongation at break, so it undergoes large elastic deformation and prevents damage to the undercut portion 29.

Next, the test material 435 shown in FIG. 5(b) obtained from the mold 44 having the L-shaped cavity 45 shown in FIG. 5(a)
A comparative test was conducted using Table 1 shows the basic physical property values of the test materials, and Table 2 shows the comparative test results.

Table 1 The dimensions of the above test material are that the thickness t is 3 mm, and the radius of curvature R1 of the corner and the radius of curvature R2 of the corner are both 1 mm.
, the width W is loomm.

(Left below) Table 2-1! Materials 1 to 3 were obtained by reacting the following formulations. 0 parts indicate parts by weight.

Materials l Isocyanate component carbodiimide modified phenylmethane diisocyanate (MDI) 40 parts (NGO content 29%) Polyol component polypropylene glycol (PPG) 4.2 parts (molecular group 3000) Crosslinking agent ethylene glycol (EG) 8 parts Catalyst 1 Triethylenediamine (TEI) A) 0.5 parts Catalyst 2 DBTr) L 0.1 parts Glass milled fiberglass (MFG) 10 parts Ne 4 2 Carbodiimide modified 1 Mrl I 38 parts
NGO content 29%) PPG (molecule jij 3000) 4.
0 part EG 7 part T E
DA O, Part 5 DBTDL
0.1 part MFG
15 parts Unit 13 Prepolymer modified MDI 40 parts (NGO
Content rate 23%) PPG (molecular group 5000) 37 parts EG
Part 8 T E D A
O, 5th part D B T D L
O, 03 part MFG
Part 15 Next, I will explain the test method.
Test material 35 10 seconds after demolding was tested using the testing apparatus shown in FIG. The main body 40 of the test material 35 is fixed to the base 41, the flat plate (iron plate) 42 is applied to the flange part 43 of the test material 35, and the deformation angle when a crack occurs in the bent part 36 by applying force F, That is, the crack occurrence angle α is read. The data for the test material 35 thus obtained are shown in Table 1.

In material *41, cracks occur at a deformation angle of 60 to 70 degrees when the silicone resin Ih layer 32 is not provided at the undercut portion, whereas cracks occur at a deformation angle of 90 degrees when the silicone resin layer 32 is provided. No cracks will occur even if the temperature is exceeded.

In addition, in material 2, the material without the silicon resin layer 32 cracks at a deformation angle of 50 to 55 degrees, but by providing the silicon resin layer 32, the crack generation angle is 70 to 80 degrees. Improved over time. This crack 37 is formed in the polyurethane layer 3 as shown in FIG.
8 and the silicone resin layer 32, and grows toward the polyurethane layer 38 side. In the figure, 39 is a urethane coating film.

In material 3, cracks 37 occur at a deformation angle of 35 to 40 degrees in the material without the silicone resin layer 32, but by providing the silicone resin layer 32,
The angle at which cracks 37 occur is improved to 50 to 60 degrees.

Similar to material 2, this crack 37 occurs at the interface between the polyurethane layer 38 and the silicone resin layer 32 and grows toward the polyurethane layer 38 side.

In Example 1-, the silicone resin layer was provided on the undercut portion of the molded product, but the silicone resin layer may be provided on a mere reinforcing portion where the molded product is subjected to a large deformation force during use.

In addition, in the above examples, DB was used as an organometallic compound catalyst.
Although TDL was used, tin dioctenate, iron stearate, lead octylate, etc. can also be used.

(Effects of the Invention) As explained in -1- above, according to the present invention, by providing a silicone resin layer on the portion of a urethane molded product that should be reinforced, a molded product that will not be damaged even if it is significantly deformed can be obtained. It will be done.

Furthermore, the organometallic compound catalyst contained in the one-liquid urethane paint promotes the reaction of the two-liquid silicone, making it possible to obtain a hardened silicone resin layer within the molding cycle of the urethane molded product.

[Brief explanation of drawings]

Fig. 1 is a manufacturing process diagram of a urethane molded product showing an embodiment of the present invention, Fig. 2(a) is a sectional view showing the state of the valve device during injection of the reaction liquid, and Fig. 2(b) is 3 is a sectional view showing the state of the valve device during circulation of the reaction liquid, FIG. 3 is a sectional view showing the outline of the mold, FIG. A cross-sectional view of the main part showing the state where the paint is spray applied, Figure (b) is a cross-sectional view of the main part showing the state where the two-component silicone is applied, Figure (e) is a cross-sectional view of the main part showing the mold clamping state, The same figure (d) is a cross-sectional view of the main part showing the mold open state,
Figure 5(e) is a sectional view of the main part showing the demolded state, Figure 5(a)
6 is a cross-sectional view of the main parts showing the mold for test material 1, FIG. 6(b) is a side view of the main parts showing test material 1, and FIG. 7 is a schematic side view showing a method for measuring the angle of crack occurrence, and FIG. 7 is a side view of the main part of the test material showing the state at the time of crack occurrence. 20... Molding mold, 21... Cavity, 22...
Fixed core, 29... Undercut part, 30... Corner part, 32... Silicone resin layer, 33... Molded product, A
... Isocyanate-based solution, B... Polyol-based solution. Fig. 2 (a) (b) Fig. 3 22 2 Prison, n; Micoah/+11/+ll 1) ,〇1ノ ζノ0 ℃ Φ--I
N, no
- Uno procedure amendment November 20, 1985 Patent Application No. 1988-236203 2, Title of invention: Method for manufacturing urethane molded products 3, Relationship with the case of the person making the amendment Patent application Office
3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Name (313)
) Mazda Motor Corporation 4, agent postal code 550 Address 1-5-3 Nishihonmachi, Nishi-ku, Osaka (Fuso Building) Name Patent attorney (7415) Namba
Country English (external name) Telephone Osaka (06) 538-1
288 No. 5, date of amendment order 7, content of amendment A, specification: (1) Table 1 on page 9; 1- to r3.000 in the flexural modulus column of each material 1, 2.3. 5.000 7.0OOJ
I will correct it as 3000 5000 7000J. seven

Claims (2)

[Claims] (1) After applying a one-component urethane paint containing an organometallic compound catalyst to the molding surface of the mold corresponding to the part to be reinforced, a two-component silicone coating on which the reaction is accelerated with the catalyst. Next, a mixture of a polyol solution and an isocyanate solution is injected into the mold cavity.
A method for producing a urethane molded product, characterized by obtaining a molded product in which a silicone resin layer is integrally formed in the portion to be reinforced. (2) The method for manufacturing a urethane molded product according to claim 1, wherein the portion to be reinforced is an undercut portion of the molded product.