JPS631332B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an unsaturated polyester resin composition for sheet molding compounds that has good workability and moldability.
More specifically, a composition containing a mixture of two types of unsaturated polyester resins having a specific hydroxyl value/acid value ratio and an isocyanate compound as the main components is prepared, and a high temperature is obtained through a reaction between these two components. The present invention relates to a composition for sheet molding compounds that can be thickened by making it into a molecular weight polyester, loses tackiness in a short period of time, is extremely easy to handle, and has excellent mechanical strength. FRP using unsaturated polyester resin is used for fishing boats,
It is used in many ways, including boats, bathtubs, tanks, pipes, containers, and chairs. Recently, sheet molding compounds (hereinafter referred to as
It is abbreviated as “SMC”. ) and bulk molding compounds are widely used. At this time, in order to make these compounds in which glass fibers are impregnated with unsaturated polyester resin into a form that is easy to handle, at present, carboxylic acids in unsaturated polyester and oxides of alkaline earth metals such as MgO, CaO, etc. By forming a metallic bond with a metal hydrate or a metal hydrate, we perform what is called B-staging in the art.
It is called SMC. However, such metal bonding is affected by moisture in the system, causing changes in the thickening properties and hardness of the compound, and moreover, it requires maturing time of 24 hours or more before it can be used for molding. Furthermore, since the hardness of the compound changes over time, there is a drawback in the molding operation that molding conditions that match the hardness must be determined empirically each time. Moreover, these metal bonds are
Since it dissociates at a high temperature of 130°C or higher, it is easy to melt and flow. However, when applied to deep molded products, it also has the disadvantage that the orientation of the glass fibers causes a deviation in strength. Furthermore, this metal bond is susceptible to hydrolysis, resulting in a physical property disadvantage in that the water resistance and boiling resistance of the molded product are significantly reduced. However, as a result of intensive research by the present inventors in order to improve the various drawbacks of the SMC manufacturing method using metal bonding described above, two unsaturated polyesters (A) and Polymerizable monomer (C) is mixed with a specific ratio of (B).
An unsaturated polyester resin composition, the main constituents of which are an unsaturated polyester resin composition dissolved in , and an isocyanate compound (D) having at least two isocyanate groups capable of reacting with the terminal hydroxyl group of the resin, is The present invention was completed by discovering that SMC can be obtained by using the same method as SMC, which loses its tackiness and is extremely easy to handle. That is, the present invention uses 40 to 90% by weight of an unsaturated polyester (A) having a ratio of hydroxy value to acid value of less than 1.5, and an unsaturated polyester (A) having a ratio of hydroxy value to acid value of 1.5 or more and having a hydroxy value of 40 to 90% by weight.
An unsaturated polyester resin composition prepared by dissolving a mixture of 60 to 10% by weight of an unsaturated polyester (B) having a molecular weight of 20 or more and a molecular weight of 800 or more in a polymerizable monomer (C), and reacting with this. After forming a composition containing an isocyanate compound (D) as an essential component and impregnating it into glass fibers, the terminal hydroxy groups of the resin (B) are mainly reacted with the isocyanate groups of the compound (D). The present invention provides an unsaturated polyester resin composition that can form an SMC that becomes non-adhesive and easy to handle in a short period of time, has less orientation of glass fibers during curing and molding, and has excellent mechanical properties. By the way, the method of modifying unsaturated polyester resin with isocyanate is already a well-known fact. A method is described in which a hydroxy group present in a resin and an isocyanate group in an isocyanate compound are reacted to increase the molecular weight, thereby producing a resin with improved physical properties such as boiling resistance and impact resistance. In addition, the specification of Special Publication No. 49-5635 and Special Publication No. 52
-11719 also discloses a technique for obtaining a non-adhesive molding composition by forming a urethane precursor from the isocyanate and a polyfunctional compound that can react with an isocyanate in an unsaturated polyester resin. However, these methods all involve forming a urethane precursor separate from the unsaturated polyester resin. Therefore, until now, a technique such as the present invention for obtaining a non-adhesive pregel in a short period of time is unknown. The present inventors have discovered that glass fibers can be easily impregnated with a reaction product of a polyisocyanate compound and an unsaturated polyester resin whose solid content has a ratio of hydroxyl value to acid value of 1.5 or more and a hydroxyl value of 20 or more. , it loses its stickiness in a short time and is flexible.
After discovering that SMC could be applied, a special application was made in 1973.
-129464 (Japanese Unexamined Patent Publication No. 55-56115), but as a result of further study, it was found that the combination of two types of unsaturated polyester resins at a specific mixing ratio as described above improves flow characteristics. They discovered that it was possible to obtain an SMC that was further improved and had excellent molded product appearance and mechanical properties. The above-mentioned "unsaturated polyester resins (A) and (B)", which are one of the main components of the composition of the present invention, are polycondensed polyester resins of a glycol component and a dibasic acid component. Ingredients include known and commonly used α,β monounsaturated dibasic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, chlorinated maleic acid, and phthalic anhydride and isophthalic acid. Acid, terephthalic acid, monochlorophthalic acid, dichlorophthalic acid, trichlorophthalic acid, hettic acid, tetrachlorophthalic anhydride, tetrabromo phthalic anhydride, endomethylenetetrahydrophthalic anhydride, tetrahydrophthalic anhydride; adipic acid, sebacic acid,
Examples include saturated dibasic acids such as succinic acid, glutaric acid, and pimelic acid, and a portion of the α,β-unsaturated dibasic acid may be replaced with this saturated dibasic acid, if necessary. On the other hand, examples of the glycol component include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol,
Triethylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-
butylene glycol, neopentyl glycol,
Hexylene glycol, octylene glycol;
Bisphenol-A, hydrogenated bisphenol, bisphenol-A/dioxyethyl ether or dioxypropyl ether adduct; or one selected from known and commonly used alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc. If necessary, a polyhydric alcohol such as trimethylolpropane or glycerin can be used in combination. Among the above-mentioned unsaturated polyesters obtained from the dibasic acid component and the glycol component in accordance with a conventional method, the unsaturated polyester (A) is an unsaturated polyester that is highly reactive with the isocyanate compound () as described below. When (B) coexists,
It has the effect of giving SMC appropriate flexibility and fluidity during molding, but unsaturated polyesters with a ratio of hydroxyl value to acid value of 1.5 or more have poor fluidity during molding and are difficult to fill into the mold. It will be sufficient. On the other hand, the unsaturated polyester (B) easily reacts with isocyanate, has a high molecular weight, and has the effect of bringing the system into a gel state. Generally, the terminals of unsaturated polyesters are either carboxylic acid or hydroxyl groups, and isocyanate groups tend to react with hydroxyl groups, and react with carboxylic acids only at high temperatures. Therefore, in order to increase the molecular weight, it is necessary to use an unsaturated polyester with many hydroxyl groups, but it is easy to impregnate into glass fibers, loses stickiness within a short time, is flexible, and has good fluidity during molding. An excellent one has a ratio of hydroxy value to acid value of 1.5 or more, preferably 1.5.
~3.0, a hydroxy value of 20 or more, and a molecular weight of 800 or more.
If this ratio is less than 1.5, a non-adhesive SMC cannot be made even if the hydroxy value is 20 or more, and even if this ratio is 1.5 or more, the hydroxy value itself is less than 20. If so, it is not possible to obtain a non-adhesive SMC. Furthermore, unsaturated polyesters with molecular weights less than 800 require the use of significantly higher amounts of isocyanate compounds to obtain non-adhesive SMCs, resulting in rapid thickening and insufficient impregnation of the glass fibers. In addition, the fluidity during melting becomes poor, and the appearance, mechanical strength, and resistance to heat discoloration of the molded product become inferior. Therefore, the molecular weight of unsaturated polyester (B) is
It should be 800 or more, preferably 1000-2000.
However, the molecular weight referred to here is 56100×
This value is calculated from 2/(hydroxy value + acid value). The usage ratio A/B of unsaturated polyester (A) and unsaturated polyester (B) is 40 to 90% by weight/60
~10% by weight. If the amount of unsaturated polyester (A) used is less than 40% by weight, the SMC will become hard and the fluidity during molding will be poor; if it exceeds 90% by weight, the SMC will become extremely sticky and difficult to work with. become less sexually active. Representative examples of the polymerizable monomer (C) include styrene, α-methylstyrene, vinyltoluene, chlorostyrene, (meth)acrylic acid and their alkyl esters, acrylonitrile, vinyl acetate, allyl acetate, Monomers such as triallyl cyanurate, triallyl isocyanurate, acrylamide, diacetonamide, etc., and of course include all monomers that can be copolymerized with unsaturated polyesters, among others, Styrene and methyl methacrylate are preferred.
The amount of these polymerizable monomers used is preferably 20 to 60% based on the total weight of the unsaturated polyesters (A) and (B).
is within the range of Moreover, a polymerization inhibitor such as hydroquinone, benzoquinone, toluhydroquinone, or t-butylcatechol can be added to these unsaturated polyesters as necessary. Typical examples of the "isocyanate compound (D)" which is the other main component of the composition of the present invention include tetramethylene diisocyanate, hexamethylene diisocyanate, 1,4-
Cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate,
Diisocyanates such as 2,6-tolylene diisocyanate and naphthalene diisocyanate; polyfunctional polyisocyanates such as polymethylene polyphenyl isocyanate; and terminal hydroxy groups of polyester polyols or polyether polyols are reacted with a diisocyanate compound to form isocyanate groups at the terminals. Added molecular weight
500 to 5000 isocyanate prepolymers. The usage amount of these isocyanate compounds (D) is
It is preferable that the entire amount of the isocyanate groups is reacted with the hydroxy groups present in the unsaturated polyester resins (A) and (B), and for this purpose, the molar ratio of hydroxy groups/isocyanate groups is usually adjusted.
1.0, but a range of 0.7 to 1.3 is sufficiently applicable. The compositions of the invention may also contain conventional curing catalysts such as benzoyl peroxide, methyl ethyl ketone peroxide, lauroyl peroxide, cumene hydroperoxide, dicumyl peroxide; t-butyl perbenzoate; dimethylaniline, naphthenes, etc. Conventional promoters such as cobalt acid, etc.; Conventional urethanization catalysts, such as cobalt octoate, dibutyltin dilaurate, etc.; Conventional fillers, such as calcium carbonate, clay, aluminum hydroxide; Conventional mold release agents, such as zinc stearate. Other organic or inorganic pigments, low shrinkage agents such as thermoplastic resins, alkaline earth metal oxides, etc. can be added. Using the composition of the present invention thus obtained, SMC
When producing
Flexible and non-adhesive SMC can be made, with less orientation of glass fibers during curing and molding, and has excellent mechanical strength, surface smoothness,
It can be made into an SMC that can give molded products with excellent appearance such as gloss and gloss. The compositions of the invention are thus particularly suitable for deep-drawn, large-sized or complex-shaped moldings, such as radiator supports, wheels, lamp housings, bumper back-up bars, transmissions, etc. Manufacture of automotive parts such as supports, bathtubs, septic tanks, etc.
Used for manufacturing large molded products such as tanks and cooling towers. Next, the present invention will be explained in detail using examples. Hereinafter, all parts and percentages are based on weight unless otherwise specified. Examples 1 to 3 and Comparative Examples 1 to 2 First, propylene glycol/neopentyl glycol/fumaric acid/isophthalic acid = 1/2/
A styrene polyester (A) consisting of 66% of an unsaturated polyester (A) with a hydroxy value of 30.3 and an acid value of 32.6 and 34% of styrene, obtained by polycondensation at a molar ratio of 2/1. A solution (hereinafter abbreviated as "unsaturated polyester resin (A)"),
Obtained by polycondensation at a molar ratio of propylene glycol/maleic anhydride/isophthalic acid = 2.7/1/1, with a hydroxy value of 106.1 and an acid value of 21.1.
A polyester consisting of 80% unsaturated polyester (B) with a molecular weight of 882 and 20% styrene.
Prepare a styrene solution of (B) (hereinafter abbreviated as "unsaturated polyester resin (B)"), and mix both resins (A) and (B) in the specified amounts as shown in Table 1. do. Next, 140 parts of calcium carbonate, 6 parts of zinc stearate, and 1 part of t-butyl perbenzoate were added to the resulting resin mixture and thoroughly stirred and mixed. Furthermore, “Isonate 143L” (Mitsubishi Chemical Industries, Ltd.)
4,4'-diphenylmethane diisocyanate;
NCO equivalent = 143) was added and mixed in the amount specified in Table 1, immediately poured and spread on a polyethylene sheet, and chopped strands cut into 1 inch pieces were uniformly dropped and dispersed so that the glass content was 30%. The film was then folded in half and compressed using a rubber roller to defoam and impregnate the glass fibers. In parallel with this, for comparison, a comparative sample was also subjected to the same procedure using the prescribed amounts shown in Table 1. Eight hours after impregnation, the formulations of Examples 1 to 3 and Comparative Example 2 were already non-adhesive when the polyethylene sheet was peeled off, and the formulations of Examples 1 to 3 and Comparative Example 2 were already non-adhesive when the polyethylene sheet was peeled off. All of them were flexible, impregnated into glass fibers sufficiently, and could be put to practical use. The formulation of Comparative Example 1 remained sticky even after 8 hours of impregnation, and its releasability from the polyethylene sheet was extremely poor.

【table】

[Table] Examples 4 to 7 and Comparative Examples 3 to 5 First, six types of unsaturated polyesters (B) as shown in Table 2 were synthesized.

[Table] Unsaturated polyester (A) obtained in Example 1,
The unsaturated polyester (B) obtained in Table 2 and
Using unsaturated polyester resin mixed in the prescribed proportions shown in the table and diluted with 20% styrene, an SMC manufacturing machine is used to produce a glass material with a glass content of 30%, a width of 1 m, and a thickness of 1 m, according to the composition shown in the table. A 2 mm SMC was prepared. Next, these SMCs of 1.8 kg were cut into 25 cm x 25 cm pieces, fed into the bottom of a deep butt mold with a bottom area of 25 cm x 25 cm and a height of 25 cm, and molded at 140°C for 5 minutes in a 100 ton press molding machine. Create a deep butt under the following conditions,
The mechanical properties and appearance of each deep butt were observed and measured. These results are summarized in Table 3. As Comparative Example 5, a conventional case using MgO is also shown.

【table】

【table】

Claims (1)

[Scope of Claims] 1 (A) 40 to 90% by weight of an unsaturated polyester having a ratio of hydroxy value to acid value of less than 1.5; (B) an unsaturated polyester having a hydroxy value of 1.5 or more and a hydroxy value of 20 or more; and 60 to 10% by weight of an unsaturated polyester having a molecular weight of 800 or more, dissolved in a polymerizable monomer (C), and (D) the terminal end of the unsaturated polyester. An unsaturated polyester resin composition for a sheet molding compound, comprising: an isocyanate compound having at least two isocyanate groups capable of reacting with hydroxyl groups.