JPS636568B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composition for sheet molding compounds that is free of stickiness in a short period of time and is extremely easy to handle, and more particularly, has a hydroxy value to acid value ratio of 1.5 or more. So, and
The present invention relates to a composition for a sheet molding compound comprising as main components an unsaturated polyester having a hydroxy value of 20 or more, a monoalcohol, a polyisocyanate compound, and a polymerizable monomer.

FRP using unsaturated polyester resin is used for fishing boats,
It is used in a wide variety of applications, including boats, bathtubs, tanks, pipes, containers, and chairs.

In recent years, sheet molding, which has good molding efficiency and does not impair the working environment, has been developed.
Molding using bulk molding compound (hereinafter abbreviated as "SMC") and bulk molding compound is widely used. At present, in order to make these compounds in which glass fiber is impregnated with unsaturated polyester into a form that is easy to handle, carboxylic acid and MgO in the unsaturated polyester,
Metallic bonds are formed with oxides and metal hydrates of alkaline earth metals such as CaO, creating a state known in the art as B-staging, resulting in a non-adhesive SMC.

However, such metallic bonds are easily affected by moisture in the system, causing changes in viscosity and hardness of the compound, and it takes longer than 24 hours before molding.
There are various disadvantages in molding operations, such as requiring maturation time longer than hours, and the hardness of the compound changing over time, so molding conditions that match the hardness must be determined empirically. There is.

Furthermore, these metal bonds are
Since dissociation occurs at high temperatures of 130°C or higher, it is easy to melt and flow, but when it is made into a deep molded product, the orientation of the glass fibers causes a deviation in strength.

Furthermore, such metal bonds are susceptible to hydrolysis, resulting in a physical property disadvantage in that the water resistance and boiling resistance of the molded product are significantly reduced.

The present inventors have conducted extensive research in order to improve the various drawbacks mentioned above due to the formation of such metal bonds, and have found that the ratio of the hydroxyl value to the acid value of the solid content is 1.5 or more, and the hydroxyl Value is 20
It has been discovered that an unsaturated polyester resin and a polyisocyanate compound within the above specified range can be used to easily impregnate glass fibers, eliminate stickiness within a short period of time, and provide highly flexible SMC. Although a patent application was filed (Tokugansho
53-129464), and as a result of subsequent research, it was found that when an extremely high molecular weight unsaturated polyester is formed by the reaction between the hydroxyl group in the unsaturated polyester and the isocyanate group in the polyisocyanate compound, melting during molding. We discovered that the resin had poor fluidity, which caused the resin to harden before it spread throughout the mold, causing short-shots (insufficient filling), and by adding monoalcohol as a third component. The present inventors have now completed the present invention by discovering that the molecular weight can be adjusted to an appropriate value and a product having excellent melt flowability, molded product appearance, and mechanical properties can be obtained.

The unsaturated polyester (A) having a ratio of hydroxyl value to acid value of 1.5 or more and a hydroxyl value of 20 or more used in carrying out the method of the present invention is an esterified polyester of a dibasic acid component and a glycol component. It refers to a condensate dissolved in a polymerizable monomer, and examples of the dibasic acid component include maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and chlorinated acid. Examples include well-known and commonly used α/β-unsaturated dibasic acids such as maleic acid, but if necessary, phthalic anhydride, isophthalic acid, terephthalic acid, monochlorophthalic acid, dichlorophthalic acid, trichlorophthalic acid, and hettic acid may be used. , tetrachlorophthalic anhydride, tetrabromophthalic anhydride, endomethylenetetrahydrophthalic anhydride, tetrahydrophthalic anhydride,
Saturated dibasic acids such as adipic acid, sebacic acid, succinic acid, glutaric acid, pimelic acid, etc. may be used in combination.

On the other hand, the glycol component includes, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, Xylene glycol, octylene glycol; bisphenol A, hydrogenated bisphenol A, bisphenol A/dioxyethyl ether or bisphenol A/dioxypropyl ether adduct; or alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc. It is selected from known and commonly used alcohols such as, and if necessary, polyhydric alcohols such as trimethylolpropane and glycerin can be used in combination.

The unsaturated polyester has a hydroxy value of 20 or more, preferably 20 to 55, and a ratio of hydroxy value to acid value of 1.5 or more, preferably 1.5 to 7.0.

Further, typical examples of the polymerizable monomer (D) containing the unsaturated polyester resin (A) include:
For example, styrene, α-methylstyrene, vinyltoluene, chlorostyrene, (meth)acrylic acid and their alkyl esters, acrylonitrile, vinyl acetate, allyl acetate, triallyl cyanurate, triallyl isocyanurate, acrylamide, diacetone acrylamide, etc. Among these monomers, particularly preferred are styrene and methyl methacrylate.

The proportion of these polymerizable monomers used is preferably 20 to 60% of the total amount of unsaturated polyester.
Within the range of % by weight.

Moreover, a polymerization inhibitor such as hydroquinone, benzoquinone, toluhydroquinone, t-butylcatechol, etc. can be added to the unsaturated polyester resin (A) as necessary.

Next, representative examples of the "monoalcohol (C)" include aliphatic alcohols such as methanol, ethanol, propanol, n-butanol, heptanol, hexanol, octanol, decanol, dodecanol, stearyl alcohol, and mericyl alcohol. Alcohols: primary alcohols such as benzyl alcohol and furfuryl alcohol.

The proportion of these monoalcohols used is such that the number of moles of hydroxyl groups in the alcohol is 5 to 30% by mole based on the total number of moles of hydroxyl groups in the unsaturated polyester resin (A). Preferably, the range is within the range. If it is less than 5 mol%, the effect of adjusting the molecular weight of the unsaturated polyester will be small;
If it is used in an excessively large amount exceeding the mol %, the SMC will become sticky because it will not have a sufficiently high molecular weight, resulting in poor workability.

Furthermore, the "polyisocyanate compound (B)"
Representative examples include tetramethylene diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate,
Diisocyanates such as xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene diisocyanate; polyfunctional polyisocyanates such as polymethylene polyphenyl isocyanate; and It is selected from commonly used isocyanate prepolymers having a molecular weight of 500 to 5,000, which are obtained by reacting the terminal hydroxy groups of polyester polyols or polyether polyols with diisocyanate compounds to add isocyanate groups to the terminals.

Regarding the amount of these polyisocyanate compounds (B) used, it is preferable that the entire amount of isocyanate groups reacts with the hydroxy groups in the unsaturated polyester, and for this purpose, the molar ratio of hydroxy groups/isocyanate groups is usually 1.0. If it is within the range of , 0.7 to 1.3, it can be used satisfactorily.

The composition of the invention thus obtained contains conventional curing catalysts such as benzoyl peroxide, methyl ethyl ketone peroxide, lauroyl peroxide, cumene hydroperoxide, dicumyl peroxide; t-butyl perbenzoate; cobalt octoate; Conventional urethanization catalysts such as dibutyltin dilaurate; Conventional fillers such as calcium carbonate, clay, aluminum hydroxide; Conventional mold release agents such as zinc stearate;
In addition, inorganic or organic pigments, low shrinkage agents such as thermoplastic resins, alkaline earth metal oxides, etc. can be added.

The composition of the present invention is particularly suitable for deep-drawn molded products, large-sized molded products, or molded products with complex shapes, such as radiator supports, wheels, lamp housings, bumper backup bars, etc.
It is used to manufacture automotive parts such as transmission supports, and large molded products such as bathtubs, septic tanks, tanks, and cooling towers.

Next, the present invention will be explained in detail with reference to Examples, but the present invention is not limited only to these Examples.

Hereinafter, all parts and percentages are based on weight unless otherwise specified.

Example 1 62% unsaturated polyester with a hydroxy value of 35.4 and an acid value of 8.2 obtained by polycondensation at a molar ratio of propylene glycol/fumaric acid/isophthalic acid = 2.3/1/1 and styrene 38 0.9 part of stearyl alcohol was dissolved at 60°C in 88.3 parts of unsaturated polyester resin consisting of 120 parts of calcium and 6 parts of styrene were added and stirred to mix.

Furthermore, “Isonate 143L” (Mitsubishi Chemical Industries, Ltd.)
4,4'-diphenylmethane diisocyanate;
After adding and mixing 4.8 parts of NCO equivalent = 143), this mixture was placed on a polyethylene sheet.
A SMC with a glass content of 30%, a width of 1 m and a thickness of 2 mm was prepared by continuous feeding by an SMC manufacturing machine.

When the polyethylene sheet was peeled off after 8 hours, no stickiness was observed and it was flexible.
SMC with sufficient impregnation into glass fibers
was gotten.

Next, 1.8 kg of this SMC was cut into a size of 25 cm x 25 cm, and this was fed to the bottom of a deep butt mold with a bottom area of 25 cm x 25 cm and a height of 25 cm, and then 100 tons of SMC was cut. 140℃ with press molding machine,
A deep butt was created by molding for 5 minutes.

The molded product thus obtained had excellent gloss and surface smoothness, was free from warping (deformation), sink marks (shrinkage), and raised glass fibers, and had extremely low occurrence of cracks.

Further, the bending strength of the bottom portion was 23.6 Kg/mm ² .

Comparative Example 1 Lacking the use of stearyl alcohol and using unsaturated polyester resin and "Isonate 143L"
The same operations as in Example 1 were repeated except that the amounts used were changed to 89.0 parts and 5.0 parts, respectively.
Created SMC.

The SMC obtained here was flexible and non-sticky, but during deep butt molding, the melt flowability was poor, and curing began before the resin spread inside the mold, resulting in the short shot being damaged. Only molded products could be obtained.

Example 2 Propylene glycol/neopentyl glycol/fumaric acid/isophthalic acid = 1.3/2/2/1
90.6 parts of an unsaturated polyester resin consisting of 66% unsaturated polyester with a hydroxyl value and an acid value of 53.1 and 19.5, respectively, and 34% styrene obtained by polycondensation at a molar ratio of , and 1000 ppm of hydroquinone, The same operation as in Example 1 was repeated, except that the amount of "Isonate 143L" used was changed to 8.9 parts, and 0.5 parts of n-butanol was used instead of stearyl alcohol.
SMC is flexible and already non-adhesive,
The molded product (deep butt) also had excellent gloss and surface smoothness, with no warpage, sink marks, or raised glass fibers, and no cracks.

In addition, the bending strength of the bottom part is 22.7Kg/mm ² ,
The bending strength measured in the direction of resin flow at the side and in the direction perpendicular to this flow is
They were 18.7 and 16.0Kg/ ^mm2 .

Comparative Example 2 Example 2 was obtained by repeating the same procedure as in Example 2, except that t-butanol was not used at all, and the amounts of unsaturated polyester resin and "Isonate 143L" were changed to 91.2 parts and 8.2 parts, respectively. The obtained SMC was flexible and not sticky, but because of its poor melt flowability, only a deep butt of a short shot could be obtained.

Claims (1)

[Claims] 1 Main components: (A) an unsaturated polyester having a ratio of hydroxy value to acid value of 1.5 or more and a hydroxy value of 20 or more, (B) a polyisocyanate compound, (C) a monoalcohol, (D) A composition for a sheet molding compound characterized by comprising a polymerizable monomer.