JPS5855164B2 - Fuhouwa polyester material - Google Patents

Description

[Detailed description of the invention] The present invention has extremely excellent injection moldability, excellent electrical properties, high mechanical strength, heat resistance, excellent surface smoothness of molded products, and flame retardant properties. It relates to an unsaturated polyester molding material in the form of certain pellets.

More specifically, it relates to an unsaturated polyester molding material having the above-mentioned properties, which is a mixture of a polyethylene terephthalate-based unsaturated polyester composition that is solid at room temperature and has a high average degree of condensation and aluminum hydroxide in a specific ratio. It is.

The purpose of the present invention is to create an unsaturated molded product that can be easily molded using a general-purpose thermosetting molding machine, has excellent electrical properties, mechanical properties, heat resistance, and surface smoothness of the molded product, and has excellent flame retardancy. To provide polyester molding materials.

In particular, it is an object of the present invention to provide an unsaturated polyester molding material that can be easily molded using a general-purpose thermosetting molding machine and that can provide molded products with high strength.

A further object of the present invention is to provide an improved molding material for the polyethylene terephthalate-based unsaturated polyester compositions disclosed in JP-A No. 48-2628 Masu Publication and JP-A No. 48-36290. .

Conventionally, it has been known that an unsaturated polyester composition generally comprises an unsaturated polyester prepolymer, an ethylenically unsaturated monomer, and a curing catalyst.

Furthermore, a resin mixture consisting of an unsaturated polyester composition, reinforcing fibers and optionally further inorganic fillers is F.
RP (Fibre Re1nforeedPlast
ics) or premix.

This FRP or premix has very useful properties (particularly good mechanical properties, heat resistance, and electrical properties), and has recently come into the spotlight as an engineering plastic that can be used mainly for electrical purposes.

For this reason, PR can be molded in the same way as thermoplastic resin.
P or premixes (hereinafter referred to as premixes) were required, and to meet this demand, premixes that could be injection molded were created and used as raw material for electrical parts.

Here, terms used in the present invention will be explained.

The term "premix" refers to a molding material prepared by adding reinforcing fibers and other additives to an unsaturated polyester composition in advance.

Further, a premix using an unsaturated polyester composition that is liquid at room temperature is called a wet premix, and a premix using an unsaturated polyester composition that is solid at room temperature is called a dry premix.

The wet premix consists of an unsaturated polyester composition that is liquid at room temperature, reinforcing fibers, inorganic fillers, thickeners, and thermoplastic polymers (with or without).

In order to improve moldability, large amounts of inorganic fillers and thickeners are used, as well as unsaturated polyester compositions that begin to cure even at relatively low temperatures.

However, since the wet premix uses an unsaturated polyester composition that is liquid at room temperature, it remains wet even with inorganic fillers and thickeners, and the material form is inevitably putty-like, lump-like, or rod-like. It has become a target.

Furthermore, since it contains a large amount of inorganic filler, its mechanical strength is low, and therefore the length of reinforcing fibers cannot be shortened in order to provide high strength, and from this point of view, such a material form is unavoidable.

Therefore, when performing creative molding, the generally used general-purpose thermosetting index molding machine cannot supply the material and cannot perform molding at all.

To create and mold this wet premix, it is necessary to use an injection molding machine dedicated to wet premixes that has a special raw material supply device.

This means that the use of a wet premix requires capital investment and is a significant economic burden.

In addition, since the wet premix uses an unsaturated polyester composition that is liquid at room temperature, the viscosity is still extremely low even with the use of inorganic fillers and thickeners, and flaking occurs in the mold during Kenzan molding. Easy to do.

In addition, because the viscosity is too low and to prevent the occurrence of flaking, the ejecting pressure is usually less than 400 kg/crA, which inevitably results in low-pressure molding, which tends to cause insufficient filling in complex molds.

For this reason, the current situation is that only relatively simple shapes can be molded, and there are significant restrictions on the shapes of molded products.

Furthermore, in order to prevent the formation of paris and improve the injection pressure, conventional wet premixes use a relatively highly active curing catalyst, which results in poor storage stability. The major drawback is that the material cannot be stored for a long time.

Due to the various drawbacks mentioned above, the wet premix cannot be called a general-purpose unsaturated polyester molding material.

Dry premix differs from wet premix in that it is in a dry state, so it can be made into granules or flakes, and therefore has the great advantage of being able to use a general-purpose thermosetting injection molding machine.

However, since this material is made in a dry process, it is necessary to use an ethylenically unsaturated monomer constituting the unsaturated polyester composition that is solid at room temperature.

This room temperature solid monomer is generally expensive.

For this reason, dry premixes have inevitably become expensive.

In addition, it has low mechanical strength and is granular or flaky, resulting in poor screw penetration and measurement stability during creation molding, resulting in problems in creation moldability.

As mentioned above, although both wet and dry premixes can be index-molded, they have major drawbacks, and their use is severely restricted, and their fruiting applications are not expanding at present.

On the other hand, premix injection molded products are mostly used in electrical machinery parts due to their excellent electrical properties, but in recent years there has been a strong demand for flame retardancy in electrical machinery parts applications.

In this case, it is absolutely necessary to make the premix flame retardant without reducing its excellent electrical properties.

Unless this is satisfied, even if Bremix can be made flame retardant,
It can be said that there is almost no practicality.

Considering how such premixes are used, it is absolutely necessary to make them flame retardant in order to make them into general-purpose molding materials that can be used for creative molding.

The inventors have overcome the drawbacks of wet and dry premixes as described above.

As a result of intensive research to develop a general-purpose unsaturated polyester molding material that is also flame retardant, we used a polyethylene terephthalate prepolymer with a high average degree of condensation as an unsaturated polyester prepolymer to create a molding material with ethylenic unsaturation.

By combining an unsaturated polyester composition containing a curing catalyst and aluminum hydroxide in a specific proportion, a pellet-form molding material with significantly improved injection moldability can be obtained. The present invention was completed based on the discovery that the present invention can be obtained.

That is, the present invention includes (a) 35 to 70 moles of terephucric acid units and 65 to 30 moles of ethylenically unsaturated dibasic acid units as the dibasic acid component, and at least 85 moles of ethylene glycol units as the glycol fraction. , and an unsaturated polyester prepolymer having an average degree of condensation in the range of 28 to 50, (O) an ethylenically unsaturated monomer, and (c) a compound of aluminum hydroxide containing a curing catalyst. In the material, the weight ratio of component (a) to fraction (D) is 9:1 to 1:1, and the sum of component (0) and component (b) to component (c) is 9:1 to 1:1. Weight ratio is 1:0.85 to 1:2.5
The present invention provides an unsaturated polyester molding material characterized by:

It is known that an unsaturated polyester composition that is solid at room temperature can be obtained by combining a polyethylene terephthalate-based unsaturated polyester prepolymer with an ethylenically unsaturated monomer, often a styrene monomer. have developed an unsaturated polyester composition using a prepolymer with an average degree of condensation ranging from 28 to 50.
By combining aluminum hydroxide with a PHR of 85 to 250, the melt viscosity increases surprisingly, and even though a considerable amount of aluminum hydroxide is included, there is surprisingly little loss in strength. The heading is the basis of the present invention.

As a result, the molding material according to the present invention has a weight of 500 kg/
High-pressure molding with indexing pressure greater than cut is now possible.

Here, the relationship between melt viscosity and injection moldability is as follows.

When injection molding a premix, low indexing pressure can cause insufficient filling in multi-cavity molds or molds with complex shapes, unevenness on the surface of the molded product, and bending or warping of the molded product. In addition, variations in the density of the molded product increase, and in some cases reinforcing fibers, in most cases glass fibers, tend to separate, making it impossible to achieve satisfactory molding.

That is, indexing pressure and injection moldability are two sides of the same coin, and the creation moldability can be expressed depending on the indexing pressure.

Good injection moldability indicates that the forming pressure is within a certain appropriate range.

An example of the relationship between indexing pressure, melt viscosity, and moldability is shown in FIG. 1.

This is an example of molding using a general-purpose thermosetting injection molding machine with a mold clamping force of 160 tons and a cylinder inner diameter of 90 mm equipped with a switch box mold having a volume of 204 cc.

The vertical axis is the indexing pressure, and the horizontal axis is the melt viscosity. That is, as the viscosity increases, the indexing pressure also increases.

Further, when the indexing pressure was 500 kg/crA or less, a lot of flaking occurred and insufficient filling occurred in some corners.

Moreover, when the indexing pressure was 1400 kg/cn (or more), cracks occurred in the molded product, and mold release became poor due to overfilling, and the occurrence of flaking was also observed.

In other words, good injection moldability means that high-pressure creation molding is possible in the case of a premix.

Conventional premix injection molding is mainly wet premix, and most of the injection molding is less than 500 kg/-, which can be called low pressure creation molding.

FIG. 1 also shows the viscosity and indexing pressure of the material of the present invention and wet and dry premixes.

The relationship between the average degree of condensation, the mixing ratio of aluminum hydroxide, and the melt viscosity of the unsaturated polyester prepolymer according to the present invention is shown in FIG. 2.

As is clear from FIG. 2, it can be seen that when the average degree of condensation exceeds 28, and when the amount of aluminum hydroxide exceeds 50 PHR, the melt viscosity increases rapidly.

Generally, when an inorganic filler such as aluminum hydroxide is present in a molten resin, the viscosity increases as the amount added increases, but by combining it with a specific unsaturated polyester composition as in the present invention, a certain average There has never been any prior knowledge that the melt viscosity increases rapidly when the degree of condensation and mixing ratio is reached, and this is a new finding.

As a result, the composition of the present invention can be molded under high pressure, and therefore does not cause insufficient filling even in multi-cavity and complicated molds, has no variation in molded product density, and provides a molding material with excellent surface smoothness. It is something.

Further, the relationship between the average degree of condensation, the mixing ratio of aluminum hydroxide, and the tensile strength of the unsaturated polyester prepolymer according to the present invention is shown in FIG.

In other words, when the average degree of condensation is below a certain value, the strength decreases at an accelerated rate as the amount of aluminum hydroxide increases, but it is clear that on a certain plate, the strength decreases surprisingly little even if the amount of aluminum hydroxide increases. It is.

Generally, when an inorganic filler such as aluminum hydroxide is introduced into the resin, the strength decreases at an accelerated rate.

The findings of the present invention are completely new.

Furthermore, it can be well understood from this knowledge that even when pelletized, it shows significantly higher strength than a dry premix.

The reason why the material according to the present invention was made into pellets was because of the above-mentioned finding that when the average degree of condensation of the prepolymer reaches a certain value or more, there is little decrease in strength even if a considerable amount of aluminum hydroxide is present.

The polyethylene terecrate-based unsaturated polyester composition referred to in the present invention includes 35 to 70 moles of terephthalic acid units as a dibasic acid component and 65 to 30 moles of ethylenically unsaturated dibasic acid units as a glycol component. This is an unsaturated polyester composition comprising an unsaturated polyester prepolymer containing at least 85 moles and having an average degree of condensation of 28 to 50, an ethylenically unsaturated monomer and a curing catalyst.

The amount of terephthalic acid units in the molecular chain constituting the prepolymer must account for 35 to 70 moles of the dibasic acid component.

This is because when the terephthalic acid component is 70 moles or more, the softening start temperature of the obtained unsaturated polyester prepolymer, and therefore the flow temperature, become significantly high, resulting in uniform crosstalk with the ethylenically unsaturated monomer. This is because it becomes difficult.

On the other hand, if the terephthalic acid component is less than 35 molar,
The softening start temperature of the prepolymer becomes low, and when this is combined with an ethylenically unsaturated monomer, the temperature at which fluidization actually starts becomes close to 50° C., and the melt viscosity decreases significantly.

For this reason, the injection pressure decreased significantly, and the injection moldability deteriorated significantly, to the point where it was not much different from the conventional wet premix.
Practicality is greatly impaired.

The softening temperature of unsaturated polyester prepolymer is 70
℃ or higher is preferable.

Determination of the softening onset temperature of prepolymers is usually done by Darra
This is done using a method called the ns mercury method.

In this method, 3z prepolymer is placed in a 17φ x 50mm test tube and 51' of mercury is added to the top of the tube.

Next, seal the test tube with nitrogen gas, and remove the test tube with 2 contents.
The temperature is increased at a rate of °C/mlyt, and the temperature at which the prepolymer is substituted onto the surface of mercury is defined as the softening point.

Furthermore, it is possible to substitute the dihydric alcohol (glycol) component in the molecular chain constituting the prepolymer with propylene glycol, diethylene glycol, etc. within a range of less than 15 moles φ.

That is, the unsaturated polyester molding material according to the present invention modified with something other than the ethylene glycol component in a range of less than 15 moles φ of the glycol component has substantially the same level of ethylene glycol as the glycol used when 100 moles of ethylene glycol is used. It shows mechanical strength and flow behavior.

However, if 15 moles or more of something other than ethylene glycol is used as a glycol component, BHBT units (bis-β-
As a result, the amount of hydroxyethyl terephthalate decreases, significantly lowering the softening onset temperature and making it difficult to form a solid at room temperature.

The average degree of condensation of the prepolymers used in the present invention must be within the range of 28 to 50.

This average degree of condensation indicates the number of repeating units of the dibasic acid, and means the number average degree of polymerization calculated from the acid value and hydroxyl value of the reaction product.

When the average degree of condensation of the prepolymer is less than 28, the melt viscosity is low, so that good injection moldability is not exhibited, and the strength is also low, so that the molding material cannot be used for practical purposes.

If the average degree of condensation exceeds 50, the melt viscosity becomes too high and mixing with other additives becomes insufficient, making it impossible to obtain a uniform molding material.

When producing the unsaturated polyester prepolymer according to the present invention, an acidic catalyst such as a sulfonate can be used as an esterification catalyst, and hydroquinone, tertiary-butylcatechol, etc. can be used as an antigelation agent. I can do it.

The method for producing the prepolymer of the present invention is preferably terephthalic acid diglycol ester, or terephthalic acid diglycol ester is substantially produced from terephthalic acid or dimethyl terephthalate and glycol, and then ethylenically unsaturated dibasic acid and divalent The alcohol is mixed with a ratio of glycol units to all dibasic acid units in the system of 1.0.
-1.5, preferably 1.15-1.4, react at 150-190'C, average degree of condensation 2.5-1.5
6. After setting the acid value to 15 or less, further heat at 160 to 220°C1
0.1~20 hours? The polycondensation reaction is preferably carried out under reduced pressure at 1 to 3 degrees Hg, with an average degree of condensation of 28 to 50 and an acid value of 4.
The following method for producing unsaturated polyester is used.

When starting from terephthalic acid or dimethyl tereclate and glycol, terephthalic acid diglycol ester obtained at a reaction rate of 90% or more is preferred.

Next, examples of the ethylenically unsaturated dibasic acid component used in the present invention include fumaric acid, maleic acid, maleic anhydride, or alkyl esters thereof, such as dimethyl ester, diethyl ester, etc. I can give you.

Next, in the present invention, as the ethylenically unsaturated monomer, both liquid and solid forms can be used, but when the unsaturated polyester prepolymer of the present invention is used, especially liquid ethylene which is easily available and inexpensive is used. It is very advantageous that sexually unsaturated monomers can be used.

Specifically, methacrylic acid in combination with styrene, chlorostyrene, t-butylstyrene, d-methylstyrene, styrene derivatives such as ethylvinylbenzene, diallylphthalate, or the ethylenically unsaturated monomers mentioned above.
Alternatively, esters of methacrylic acid and the like are used.

Furthermore, the above monomers may also be used in the form of a mixture of two or more.

The amount of the ethylenically unsaturated monomer used in the present invention must be approximately 10 to 50% by weight based on the total weight of the unsaturated polyester prepolymer and the ethylenically unsaturated monomer.

For example, if the unsaturated polyester composition is contained in an amount exceeding 50% by weight, the unsaturated polyester composition will be solid at room temperature;
At temperatures above 0'C, the viscosity decreases extremely, making it difficult to control the flow during kenzan molding.

On the other hand, if the weight is less than 10 φ, the physical properties of the material after curing will be poor and the unsaturated polyester resin will not be able to exhibit sufficient performance.

Next, the curing catalyst used in the present invention is one that is commonly used in F'RP curing catalysts, such as benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, methyl ethyl ketone peroxide, or azobisisobutyronitrile. be.

The amount used is preferably 0.05 to 2.5 weight φ in the unsaturated polyester composition.

Next, the aluminum hydroxide used in the present invention is a powder, preferably 60 μm or less, more preferably 20 μm or less.

The aluminum hydroxide used in the present invention is used in an amount of 85 to 250 parts by weight, preferably 100 to 200 parts by weight, based on 100 parts by weight of the total weight of the unsaturated polyester prepolymer and the ethylenically unsaturated monomer. .

Here, when aluminum hydroxide is less than 85 parts by weight, it does not contribute much to the increase in melt viscosity.

On the other hand, if the amount exceeds 250 parts by weight, the strength of molded products made from this material decreases rapidly, making it unusable as a molding material.

Depending on the purpose of use, the unsaturated polyester molding material provided by the present invention may be inorganic fillers (calcium carbonate, clay, alumina, silica, etc.) such as various reinforcing fibers, glass fibers, carbon fibers, organic fibers, etc. , barium sulfate, etc.), low-shrinkage polymers (thermoplastic resins such as polyethylene, methyl methacrylate polymers, polystyrene, etc.), pre-release material, colorants, stabilizers, etc., before use.

Various methods can be used to produce the molding material according to the present invention.

The prepolymer and the ethylenically unsaturated monomer can be mixed by adding the monomer to the molten state of the prepolymer and dispersing it, or by adding the monomer to the powdered prepolymer and mixing. A blending method may also be used.

However, preferably the unsaturated polyester prepolymer 9
A method is used in which an ethylenically unsaturated monomer heated to 50 to 100°C is added and mixed into a 0 to 140°C melt.

Further, the curing catalyst may be added at the stage of mixing the prepolymer and the monomer, or may be added at the subsequent pelletizing step.

In addition, when adding a low-shrinkage polymer, in advance,
It is also possible to dissolve the low shrinkage polymer in the monomer and then add it.

Alternatively, a triblend method may be used.

Next, aluminum hydroxide or, if necessary, other substances are added to the unsaturated polyester composition, which is solid at room temperature and consists of a prepolymer, a monomer, and a curing catalyst, to form a pelletized molding material.

As a method, a tri-blend method of a powdered unsaturated polyester composition and powdered aluminum hydroxide, or a melt dispersion method in which aluminum hydroxide is mixed into a completely molten state of the unsaturated polyester composition are used.

The unsaturated polyester composition thus obtained, which is solid at room temperature, is processed into pellets or granules using a device such as an extruder or a Henschel mixer.

In this pelletizing step, reinforcing fibers such as glass fibers, carbon fibers, and organic fibers can be incorporated.

The unsaturated polyester molding material of the present invention thus obtained is in the form of uniformly shaped pellets, and can be easily molded using a general-purpose thermosetting molding machine, and can be molded using a conventional wet premix. On the other hand, since high-pressure molding is possible, products with complex shapes can be easily obtained, and high-pressure molding provides molded products with good surface smoothness and good dimensional accuracy.

Furthermore, despite being in pellet form, unlike dry premix, it has high strength and can be used as an engineering plastic in a wide range of applications.

In particular, the material of the present invention is flame retardant, so it is suitable for electrical parts.
Can be used widely.

The molding materials of the invention are suitable for creative molding or can also be used in other molding methods, such as compression molding or transfer molding.

Aspects of the present invention will be explained in detail below using examples.

Example 1 13 ethylene glycol in 6 moles of dimethyl terephthalate
．． 2 mol and 0.0 mol of calcium acetate, which is a transesterification catalyst.
Bis-β-hydroxyethyl terephthalate (bis-β-hydroxyethyl terephthalate (
Hereinafter, BHET) was obtained.

After adding 4.0 mol of fumaric acid to the BHBT obtained here and carrying out a dehydration reaction at normal pressure for 3 hours,
Dehydration and deethylene glycol reaction were performed under vacuum at a temperature of 200° C. for 6 hours to obtain an unsaturated polyester prepolymer (referred to as method a).

This prepolymer has an acid value of 1.3 and a softening temperature of 89°C13.
ηsp/cba0 with orthochlorophenol solvent at 0°C
．． 47, and the average degree of condensation is 38.

500 g of styrene is added to this prepolymer 150 (H') and melt-mixed at 110°C to 120'C (method b).

After uniformly mixing, cool and dicumyl peroxide 2
1' and zinc stearate 2M', aluminum hydroxide 3
After mixing 000f and 2300 g of glass fiber, they are put into an extruder and pelletized (method C).

The obtained pellets are injection molded using an injection molding machine for thermosetting resins (IR-8OA manufactured by Toshiba Machine).

The molds used are a test piece for measuring electrical insulation resistance, a test piece for measuring tensile strength, a test piece for measuring thermal deformation temperature, and a test piece mold for measuring Izot impact value.

Creation pressure 800 kg/cJ'! Continuous molding is carried out with a cylinder temperature of 80° C., a mold temperature of 145° C., and a curing time of 50 seconds (method d).

Table 1 shows the performance of the obtained molded product.

Example 2 The unsaturated polyester prepolymer obtained in Example 1-a method was mixed in the same manner as in Example 1-b method with different amounts of styrene, and after melt mixing, it was cooled to 65°C and used as a curing catalyst. Dicumyl peroxide is added, taken out into a predetermined amount of aluminum hydroxide, and pulverized. Furthermore, zinc stearate as a mold release agent and glass fiber as a fiber reinforcing agent are added, and pellets are obtained using an extruder.

Table 2 shows the viscosity of the obtained pellet and the performance of the Kenzan molded product.

Here, the melt viscosity was measured using a Koka flow tester manufactured by Shimadzu Corporation, with nozzle dimensions L/D = 10 mm/2 mm, and temperature 80°C.
, measured with a load of 100 kg.

The Kenzan pressure is the injection pressure when molding was performed using the same injection molding machine as in Example 1.

The bending strength and bending modulus of injection molded products meet ASTM D-
790-66.

If the weight ratio of styrene is 504 or more based on the total weight of the unsaturated polyester prepolymer and styrene, the melt viscosity will be extremely low and a satisfactory molded product will not be obtained due to low pressure molding, and if it is less than 10%, the bending strength will be extremely low. It is low and has a practical problem.

Reference Example 1 An unsaturated polyester prepolymer was obtained by changing the molar ratio of dimethyl terephthalate and maleic acid, which is an ethylenically unsaturated dibasic acid, and reacting the glycol component in the same manner as in Example 1-a.

Furthermore, an unsaturated polyester composition was obtained by changing the blending ratio of styrene monomer as an ethylenically unsaturated monomer to the prepolymer obtained here.

Its properties are shown in Table 3.

Among the dibasic acid components, the mole of dimethyl terephthalate is 3
If it is less than 5 φ, the softening temperature of the unsaturated polyester composition will be 50° C. or less, and if it is more than 70 moles, dispersion with styrene will be poor.

Reference Example 2 The molar ratio of ethylene glycol and propylene glycol was changed to the acid component obtained in Reference Example 1, in which the molar ratio of the terephthalic acid component to the unsaturated acid was 1/1, and the method of Example 1-a was used. A similar reaction was carried out to obtain an unsaturated polyester prepolymer.

Furthermore, an unsaturated polyester composition was obtained by blending 40% by weight of chlorofluoride as an ethylenically unsaturated monomer into the prepolymer obtained here.

Its properties are shown in Table 4. When the ethylene glycol component among the glycol components is less than 85 mol φ, the softening temperature of the prepolymer will be 70°C or lower, and therefore the softening temperature of the unsaturated polyester composition will be 50°C or lower.

Example 3 The mixture of the unsaturated polyester prepolymer and styrene monomer obtained in Example 1 was completely melted, and the melt was mixed with varying amounts of aluminum hydroxide, cooled, and then pulverized.

A predetermined amount of dicumyl peroxide and glass fiber are added to the pulverized product, and pellets are obtained using an extruder.

Table 5 shows the melt viscosity of the obtained pellets and the physical properties of the created molded product.
Shown below.

If Al(OH)3 is less than 50 parts by weight with respect to 100 parts by weight of the total weight of the unsaturated polyester prepolymer and ethylenically unsaturated monomer, the melt viscosity will be low and low pressure molding will be required, and if it is 250 parts or more, Mechanical strength decreases.

Comparative Example 5 120 parts of glass fiber was added to 100 parts by weight of a commercially available general type unsaturated polyester composition (phthalic anhydride type), and 130 parts by weight and 150 parts by weight of Al(OH)3 were added and mixed to obtain a premix. .

The viscosity of the premix is shown in Table 6. -1itu type afllt” Al(OH) in IJ ester composition
Even if a large amount of 3 was added, the viscosity did not increase as expected.

Example 4 In the method of Example 1-a, an unsaturated polyester prepolymer and a styrene monomer were melt-mixed by changing the condensation time to change the average degree of condensation, and the melt was mixed with varying amounts of aluminum hydroxide. , grind after cooling.

A predetermined amount of dicumyl peroxide and glass fiber are added to the pulverized product, and pellets are obtained using an extruder.

Tables 7, 8, and 9 show the melt viscosity of the pellets obtained, the bending strength of the injection-molded product, and the dispersibility of the molding material.

Blend composition Unsaturated polyester prepolymer 67 parts by weight (varies average degree of condensation) Styrene monomer 33 tt glass fiber 120 Dicumyl tsum oxide 2 Al(OH) 3 Example 5 General type unsaturated polyester prepolymer with ethylenically unsaturated 120 parts by weight of glass fibers were added to 100 parts by weight of an unsaturated polyester composition that was solid at room temperature and used diallyl phthalate prepolymer as a monomer, and further added Al(O
H) Obtain compositions in which the amount of 3 added is changed.

2 parts by weight of dicumyl peroxide was added to this to obtain a molding material (Comparative Example 6).

This and the molding material of the present invention of Example 3 were creatively molded, and the bending strength was measured. Table 10 shows the results.

Compared to the molding material of the present invention, where the strength decrease is small due to the addition of Al(OH)3, the strength decrease is large in the dry premix using the -1i19 type unsaturated polyester prepolymer and diallyl phthalate prepolymer.

Example 6 A solution prepared by dissolving a predetermined amount of polymethylmethacrylate in the unsaturated polyester prepolymer obtained in Example 1 and styrene monomer was mixed and melted, and the melt was mixed with aluminum hydroxide, glass fiber, zinc stearate, and A predetermined amount of dicumyl peroxide is added and mixed 7, and pellets are obtained using an extruder.

The obtained pellets are processed using a BMC molding machine manufactured by Ishikawajima Harima*R.
The results shown in Table 11 were obtained by injection molding using X-16OA.

Commercially available BMC and PMC were molded as comparative materials.

A test piece mold was used to measure tensile strength, bending strength, Izod impact value, shrinkage rate, and insulation resistance value.

The molding conditions are as follows.

Cylinder temperature: Example is 80℃, BMC is 50'CP
MC is 90°G Mold temperature; Example, BMC is 160'C, PMC is 19
0°C1 Injection time: 25 sec Example composition (parts by weight) Unsaturated polyester pre-67 Polymer styrene monomer 33 Polymethyl methacrylate-17 Polymer glass fiber Al(OH)3 Dicumyl peroxystearate Zinc 20 30 Do 2 1.5

[Brief explanation of drawings]

FIG. 1 shows the relationship between injection pressure, molten viscous nitride, and moldability. FIG. 2 shows the relationship between the average degree of condensation of an unsaturated polyester prepolymer, the mixing ratio of aluminum hydroxide, and the melt viscosity. FIG. 3 shows the relationship between the average degree of condensation of unsaturated polyester prepolymers, the mixing ratio of aluminum hydroxide, and the tensile strength.

Claims (1)

[Claims] 1 (a) 35 to 35 terephthalic acid units as the dibasic acid component
(b) an unsaturated polyester prepolymer consisting of 70 mol East ethylenically unsaturated dibasic acid units 65 to 30 mol φ and 85 mol φ or more ethylene glycol units as a glycol component and having an average degree of condensation of 28 to 50; In a molding material containing a curing catalyst in a mixture of a saturated monomer and (c) aluminum hydroxide, the weight ratio of the (a) component to the (b) component is 9:1 to 1:1. , naturally (
An unsaturated polyester molding material characterized in that the weight ratio of the sum of components (a) and (b) to component (c) is 1:0.85 to 1:2.5. 2 (a) 35 to 35 terephthalic acid units as dibasic acid component
70 moles and 65 to 30 ethylenically unsaturated dibasic acid units
Contains at least 85 moles of ethylene glycol units as a mole glycol fraction, and has an average degree of condensation of 28
-50, unsaturated polyester prepolymer, (b) ethylenically unsaturated monomer, (c) aluminum hydroxide, curing catalyst, and (e) reinforcing fiber, inorganic filler, low shrinkage. In a molding material consisting of at least one component selected from commercial polymers, the weight ratio of component (A) to component (D) is 9:1 to 1, and the weight ratio of component (A) and component (D) is 9:1 to 1. The weight ratio of the sum of the components and the component (c) is 1:0.
An unsaturated polyester molding material having a ratio of 85 to 1:2.5.