JP5121663B2 - Maleic anhydride-modified polypropylene and resin composition containing the same - Google Patents

Description

  The present invention relates to maleic anhydride-modified polypropylene and a filler-reinforced polyolefin resin composition containing the same.

  Propylene-based resins are widely used as various molded products because they have many excellent properties such as moldability, heat resistance, chemical resistance, mechanical properties and environmental characteristics. Also, reinforced propylene resin, a general-purpose resin, with glass fiber, etc., impact resistance, rigidity, heat resistance, mechanical strength such as tensile strength and bending strength, and durability performance such as creep properties and vibration fatigue Improvements are being made. In particular, it is important to improve durability from the viewpoint of resource saving. However, since polypropylene is a nonpolar polymer and has low affinity with polar substances such as glass fibers, the interfacial adhesion to the substance is poor. Even if a propylene resin and a polar filling substance are simply melt-kneaded, the above reinforcement It is difficult to obtain an effect. As a method to remedy this problem, a modified propylene resin in which maleic anhydride or the like is grafted to a propylene resin has been developed. By adding this, the interfacial adhesion between the propylene resin and the polar filling material is improved. Is planned. This maleic anhydride-modified propylene-based resin is produced by grafting maleic anhydride onto polypropylene using radicals generated by an organic peroxide or a thermal decomposition method as an initiator. Increasing the graft amount of this maleic anhydride increases the affinity with the polar filling material, and as a result, the interfacial adhesion is improved and the above-mentioned performance can be expected.

The production of the above-described modified polypropylene includes a solvent method in which a reaction is conventionally performed in a solvent and a melting method in which a reaction is performed in a molten state using a kneading extruder (Patent Documents 1 and 2).
The solvent method has an advantage that a relatively high graft acid-modified polypropylene can be obtained. That is, the amount of grafting can be easily increased by increasing the reaction time or reacting with more radical agents. On the other hand, there is a drawback that the molecular weight is also significantly reduced. That is, since polypropylene has a tertiary carbon in its molecular skeleton, a β-cleavage reaction of the polypropylene molecular chain also occurs during the graft reaction, resulting in a competitive reaction of both reactions. In general, the β-cleavage reaction rate is faster than the graft reaction rate, and it is known that increasing the graft amount results in a significant increase in melt flow rate, that is, a significant decrease in molecular weight. Yes. The modified polypropylene having a significantly reduced molecular weight can improve the interfacial adhesion with the polar filler, but cannot be expected to have an entanglement effect with the matrix resin, resulting in a decrease in mechanical properties. Furthermore, if the graft amount is too high, the modified polypropylene itself is too polar, so when blended with the matrix resin, it becomes incompatible with the matrix resin, forming an incompatible interface between them, and the matrix resin Reduces its own strength. In addition, in the solvent method, since it is difficult to completely remove aromatic compounds such as toluene, xylene and chlorobenzene which are usually used as a reaction solvent, a relatively high content remains in the modified polypropylene, and a resin in which it is blended Since they are contained in the molded product, it becomes difficult to use the resin molded product for automobile interior parts, food packaging, and the like that are strictly regulated by volatile organic compounds (VOC).

  In addition, the modified polypropylene produced by the melt method can remarkably reduce the degree of lowering the molecular weight compared to that produced by the solvent method, but the graft amount is considerably low because grafting is difficult to proceed. In order to improve the interfacial adhesion with the filler, it is necessary to add a considerably large amount of an acid-modified polypropylene polymer to the matrix resin, and a large amount of unreacted acid content (that is, no graft reaction). And ethylenically unsaturated compounds such as unsaturated carboxylic acids), and further, it contains a large amount of other by-products because it is treated at a high temperature. In particular, the unreacted acid content reacts with a functional group on the treated surface such as a surface-treated filler, such as glass fiber, to inhibit the binding between the acid-modified polypropylene and the filler surface, and further remains in the molded product. Since a large amount of unreacted acid content and other by-products adversely affect the physical properties and environment of the molded product, it is not preferable that the modified polypropylene contains them.

  As a method for removing this unreacted acid content, the obtained modified polypropylene is dissolved in a solvent and then reprecipitated to remove the unreacted acid content (Patent Document 3), or heat drying at a temperature of 60 ° C. or higher. Although the method (patent document 4) etc. which do are proposed, the former process is disadvantageous in terms of cost while it is difficult to completely remove the cleaning solvent as described above. Further, the latter treatment does not sufficiently remove the unreacted acid content.

  Regarding the relationship between the amount of maleic anhydride grafted in acid-modified polypropylene and the melt flow rate (MFR), the graft amount is usually high to some extent as described above, and the upper limit of the melt flow rate is preferably about several hundreds if possible. For example, Patent Document 5 describes a method for producing a propylene-based resin composition having excellent appearance of a molded body, a balance between rigidity and impact resistance, and an excellent balance between impact resistance and heat resistance. As the modified polypropylene blended in the resin composition, a graft ratio of 0.01 to 10% by weight and a melt flow rate of 0.1 to 500 g / 10 min are described. 200 g / 10 min maleic acid graft ratio of 0.3 wt%, MFR 70 g / 10 min, maleic acid graft ratio 0.8 wt% Maleic acid-modified polypropylene resin is disclosed. Patent Document 6 discloses a filler-containing polyolefin resin composition, and the polyolefin resin blended therein is a graft ratio of 0.30 to 20% by weight, particularly preferably 0.50 to 10% by weight. And a melt flow rate (MFR) of 400 g / 10 min or less is disclosed, and from the viewpoint of mechanical strength and production stability, 5 to 400 g / 10 min is preferred, and more preferably 10 to 200 g / 10 min. In particular, it is disclosed that it is 20 to 90 g / 10 min. Specifically, the MFR is 70 g / 10 min, the maleic acid graft ratio is 0.64% by weight (Example 1), and the MFR is 350 g / min. A maleic acid-modified polypropylene resin having a maleic acid graft ratio of 0.82% by weight in 10 minutes is disclosed.

Furthermore, Patent Document 7 discloses a method for producing an acid-modified polypropylene polymer obtained by grafting maleic anhydride in the presence of a solvent using an organic peroxide having a peroxycarbonate structure, and the grafting rate. (GR) is 0.5 to 10%, more preferably 1 to 5%, still more preferably 1.2 to 4%, and the melt flow rate (MFR) is 1 to 1000 g / 10 minutes, more preferably 1 to 500 g. / 10 minutes, more preferably about 1 to 300 g / 10 minutes, an acid-modified polypropylene polymer is disclosed. Specifically, Examples 1 to 5 have a grafting rate of 0.5 to 1.3 mass. %, A maleic anhydride modified polypropylene with a melt flow rate of 4 to 151 g / 10 min is disclosed.
JP 58-17156 A JP-A-4-198243 JP-A-54-99193 JP-A-56-95914 JP 2006-56971 A Japanese Patent Laid-Open No. 2004-197068 JP 2006-249340 A

As described above, various maleic acid-modified polypropylenes for improving the adhesion between the filler and the polyolefin resin in the conventional filler-containing polyolefin resin are known. Generally, the melt flow rate is 500 g / 10 minutes or less is preferred. What is actually obtained at a melt flow rate of 500 g / 10 min or less has a grafting rate with maleic anhydride of less than 1% or at most 1.5%. In addition, no satisfactory results have been obtained. In particular, a maleic acid-modified polypropylene in which the mechanical strength and durability of the filler-containing polyolefin resin can be sufficiently improved and the volatile organic compound is sufficiently removed has not been obtained. .
In addition, the development of filler-containing polyolefin resins with improved mechanical strength and durability, such as impact resistance, rigidity and heat resistance, and reduced volatile organic components and unreacted acid content in molded products is also desired. It was rare.
Accordingly, an object of the present invention is to provide a maleic anhydride-modified polyolefin and a filler-reinforced polyolefin-based composition containing the same, which can eliminate the disadvantages of the prior art.

  As a result of intensive studies to solve the above problems, the present inventors have a specific range of melt flow rate that has a relatively high specific graft amount and is higher than a melt flow rate that has been considered to be preferable in the past. The specific maleic anhydride modified polypropylene has a small amount of addition when blended into a filler reinforced polyolefin resin composition, despite the higher melt flow rate values previously considered preferred. Even if it is, the mechanical strength and durability can be improved by improving the interfacial adhesion between the polyolefin resin and the filler without lowering the physical properties of the resin composition, and the maleic anhydride-modified polypropylene is volatile. Since it can be obtained as a significantly reduced content of volatile organic compounds (hereinafter also referred to as VOC), Be formulated into a dosage reinforced polyolefin resin composition, it found that less filler reinforced polyolefin resin composition of VOC content can be obtained, thereby completing the present invention. The melt flow rate (g / 10 min) used in the present invention is measured at a temperature of 230 ° C. and a load of 21.18 N based on JIS-K7210.

Therefore, the present invention
(1) Maleic anhydride-modified polypropylene having a graft amount of maleic anhydride of 1.8 to 2.5% by mass and a melt flow rate (MFR) of 600 g / 10 min or more and 700 g / 10 min or less, graft amount of maleic anhydride, and the measured values in the following manner.
Measurement of grafting amount of maleic anhydride:
Maleic anhydride-modified polypropylene is completely dissolved in 140 ° C. xylene, cooled, precipitated with acetone and filtered, and the resulting precipitate is heated and vacuum dried at 140 ° C. and 15 mmHg for 1 hour. Was heated at 120 ° C. and 200 kgf / cm ² for 1 minute to prepare a film having a thickness of 100 μm, and an infrared absorption spectrum of the prepared film was measured. The amount of maleic anhydride grafted was determined by absorption at 1780 cm ^−1. Quantify.
(2) The above-mentioned (1), wherein the content of non-grafted maleic anhydride (including maleic anhydride oligomer) contained in the maleic anhydride-modified polypropylene is 25% by mass or less with respect to 100% by mass of the grafted maleic anhydride. Maleic anhydride-modified polypropylene as described in
(3) A filler-reinforced polyolefin-based resin composition containing the maleic anhydride-modified polypropylene according to any one of (1) and (2) above,
(4) The filler-reinforced polyolefin resin composition according to (3), wherein the maleic anhydride-modified polypropylene content relative to the total amount of the filler and the polyolefin resin is 0.01 to 3% by mass,
(5) The filler-reinforced polyolefin resin composition according to (3) or (4), wherein the filler is fibers.
(6) The filler-reinforced polyolefin resin composition according to (5), wherein the fibers are selected from the group consisting of glass fibers, carbon fibers, and natural fibers,
About.

  When the maleic anhydride-modified polypropylene of the present invention is blended in a filler-reinforced polyolefin resin composition, the tensile strength, bending strength, flexural modulus, impact of the filler-reinforced polyolefin resin composition can be added in a small amount. Strength and fatigue strength can be improved, and the maleic anhydride-modified polypropylene of the present invention has a low content of volatile organic compounds. Therefore, even if it is blended in a filler-reinforced polyolefin resin composition, Contamination with a volatile organic compound in the agent-reinforced polyolefin resin composition can be remarkably reduced. Therefore, the filler-reinforced polyolefin resin composition containing the maleic anhydride-modified polypropylene of the present invention can reduce the thickness of the molded product obtained from the composition and can reduce the weight of the molded product. In addition, it can be blended for reinforcement in recycled resin products, and further, the use of volatile organic compounds in strict regulations on the content of volatile organic compounds is expected to be expanded to automotive interiors and food packaging.

The present invention is described in detail below.
As described above, the maleic anhydride-modified polypropylene of the present invention (hereinafter, also simply referred to as the modified polypropylene of the present invention) is characterized by having a specific graft ratio and melt flow rate (MFR). Low content of water-soluble organic compounds and ungrafted maleic anhydride component (ungrafted maleic anhydride) (unreacted maleic anhydride component and maleic anhydride oligomer: hereinafter also referred to simply as unreacted acid content) Although the maleic anhydride-modified polypropylene of the present invention, which is strictly characterized by the low content of these non-grafted maleic anhydrides, corresponds to a composition, in the present invention, for convenience, It is called maleic anhydride-modified polypropylene.
As apparent from the above, the maleic anhydride-modified polypropylene of the present invention is suitable as an additive to the filler-reinforced polyolefin resin composition. The maleic anhydride-modified polypropylene can be synthesized, for example, as follows.
For example, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate is used as a solvent, and raw material polypropylene, maleic anhydride, and organic peroxide such as tertiary butyl peroxy 2-ethylhexyl carbonate are arbitrarily selected. In this order or together, the maleic anhydride-modified polypropylene of the present invention can be obtained by graft polymerization of maleic anhydride onto polypropylene under normal heating, for example, at about 150 ° C.

  As the raw material polypropylene, those usually having a melt flow rate of about 10 g / 10 min or less are preferable, and commercially available powdery or granular polypropylene can be used. In addition, the value of the melt flow rate is a value measured at a temperature of 230 ° C. and a load of 21.18 N according to JIS-K7210 as described above. Usually, a raw material polypropylene having an average particle diameter of about 5 to 0.01 mm, preferably about 2 to 0.05 mm is used. In the present invention, powdery polypropylene is preferably used. The amount of maleic anhydride used relative to the raw material polypropylene is not particularly limited, but is usually about 2 to 100 parts, preferably 100 parts by weight of the raw material polypropylene (the following parts represent parts by weight unless otherwise specified). Is about 20 to 80 parts. The organic peroxide is not particularly limited as long as the maleic anhydride-modified polypropylene of the present invention can be obtained, but the above tertiary butyl peroxy 2-ethylhexyl carbonate is preferable. Although the amount of organic peroxide used varies depending on the reaction conditions and the like, it cannot generally be said, but usually 0.1 to 30 parts, preferably 0.5 to 25 parts, more preferably 100 parts of raw material polypropylene. 2 to 20 parts, more preferably 4 to 18 parts.

  The reaction temperature is not particularly limited as long as it is a temperature at which the graft reaction is carried out, but is usually 60 to 250 ° C, preferably 70 to 180 ° C, more preferably 80 to 170 ° C. The reaction at a high temperature is preferable in that the reaction time can be shortened. In that case, the reaction temperature is about 100 to 180 ° C, more preferably about 120 to 170 ° C. What is necessary is just to determine reaction time suitably by relationship with reaction temperature etc. so that the maleic anhydride modified polypropylene of this invention may be obtained. Further, the amount of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate used as a solvent is not particularly limited, and an optimum amount for the reaction may be appropriately determined. Usually, it is 1 part or more, preferably 10 parts or more, more preferably 20 parts or more with respect to 100 parts of the raw material polypropylene. Although there is no particular upper limit, it is usually 500 parts or less, preferably 400 parts or less, for economic reasons. More preferably, it is 350 parts or less, More preferably, it is about 300 parts or less.

  After the graft reaction, removal of the unreacted acid content from the resulting maleic anhydride-modified polypropylene can be performed by washing with a solvent capable of dissolving the unreacted acid content. The washing may be performed once, but is preferably repeated a plurality of times and about 2 to 5 times in order to reduce the amount of unreacted acid. The solvent may be any solvent that can dissolve the unreacted acid component, but a low boiling point solvent is preferable in consideration of removal of the cleaning solvent by drying under heating and reduced pressure after cleaning. Although not particularly limited, a ketone solvent such as methyl ethyl ketone is a preferred one.

The maleic anhydride-modified polypropylene of the present invention obtained as described above has a grafting amount of maleic anhydride of 1.8 to 2.5% by mass (in this specification, unless otherwise specified,% is% by mass). Meaning). The graft amount is preferably 2% or more, more preferably more than 2%, and the upper limit is preferably 2.4% or less, and more preferably 2.3% or less. One preferred is that the graft amount is 1.8 to 2.3%, and one of the most preferred is that the graft amount is more than 2% and not more than 2.3%. be able to.
The melt flow rate is in the range of 500 to 800 g / 10 minutes, preferably greater than 500 g / 10 minutes, more preferably greater than 550 g / 10 minutes, and even more than 600 g / 10 minutes. is there. Although an upper limit should just be 800 g / 10min or less, Preferably it is 750 g / 10min or less, More preferably, it is about 700 g / 10min.
The unreacted acid content is usually 30% or less, preferably 25% or less, more preferably 20% or less in the present invention when the grafted acid content is 100%. Further, a more preferable 15% or less, or 10 to 0% can be obtained. The smaller the better, the better the economics and the like, if the unreacted acid content contained in the maleic anhydride-modified polypropylene of the present invention is about 0.5% or less with respect to the whole modified polypropylene, Even when it is added to the filler-reinforced polyolefin resin composition, since the addition amount is small, it seems that there is almost no adverse effect in normal use.

  Furthermore, the modified polypropylene of the present invention is characterized by a low volatile organic compound content, and the total of volatile organic compounds measured by headspace gas chromatography when the modified polypropylene is heated at 80 ° C. for 1 hour. The amount is 100 μg / g or less, preferably 80 μg / g or less, more preferably 60 μg / g or less. One of the most preferred is 50 μg / g or less, and in some cases 40 μg / g or less.

  The modified polypropylene of the present invention obtained as described above is an additive for polyolefin resins, for example, a compatibilizer for improving compatibility or an adhesive polypropylene for improving adhesiveness, as in the case of conventional acid-modified polyolefins. In addition, it is useful for known uses such as nanocomposites.

Next, the filler reinforced polyolefin resin composition containing the modified polypropylene of the present invention will be described.
The resin composition can be obtained by kneading a modified polypropylene, a filler, and a polyolefin resin by a conventionally known method.
The blending amount of the modified polypropylene of the present invention in the resin composition depends on the kind of the filler, but is usually about 0.01 to 3% when the total mass of the polyolefin resin and the filler is 100%. Preferably it is 0.1% or more, more preferably 0.3% or more, still more preferably 0.4% or more, and in some cases 0.5% or more is optimal, % Or less is preferable, more preferably 2% or less, and a sufficient effect is exhibited even at 1.5% or less or 1% or less.
When the blending amount is 0.01% or less, the effect as a compatibilizing agent is lowered, and mechanical properties cannot be obtained. On the other hand, if it exceeds 3%, the improvement in mechanical properties with respect to the blending amount is reduced, which is disadvantageous in terms of cost.
In the filler-reinforced polyolefin-based resin composition containing the modified polypropylene of the present invention, the ratio of grafted maleic anhydride to the entire resin composition (also referred to as the graft ratio relative to the total amount of the resin composition) is 0.003 to 0.00. About 06% is preferable, more preferably about 0.006 to 0.06%, and still more preferably about 0.01 to 0.06%. The upper limit may be 0.04% or less in consideration of economics and the like. Furthermore, 0.03% or less is also preferable. Moreover, the outstanding effect of this invention is fully exhibited even if it is 0.02% or less.

In the present invention, a filler-reinforced polyolefin resin composition containing the modified polypropylene of the present invention is a resin composition in which a filler is added to a polyolefin resin for the purpose of improving strength and the like in a molded product. The system resin is a matrix resin.
The polyolefin resin used as the matrix resin is not particularly limited as long as it is a polyolefin resin. Typical examples include polypropylene resins and polyethylene resins. Examples of polypropylene resins include propylene homopolymers and copolymers of propylene and other copolymer components. Examples of polyethylene resins include ethylene homopolymers and copolymers with other copolymer components. Among these, a polypropylene resin is more preferable, and a propylene homopolymer and a copolymer of propylene and ethylene are more preferable.

  An engineering plastic such as polyester, polyamide, polyphenylene sulfide, polyphenylene ether or polyphenylene oxide, or an elastomer such as EPR or EBR may be blended with the matrix resin.

  The filler to be blended in the matrix resin may be any of the commonly used fillers such as glass fiber, carbon fiber, metal fiber, aromatic polyamide fiber, kenaf fiber, hemp fiber, bamboo fiber, polyester fiber, Mention may be made of fibers such as nylon fibers, jute fibers, cellulose fibers or wood flour, or inorganic materials such as calcium carbonate, magnesium hydroxide, talc, mica or clay. These may be used alone or in combination of two or more. For example, a composite material in which an inorganic material and an organic material are combined may be used. Among these, fibers are preferable, and more preferable examples include glass fiber, carbon fiber, and natural fiber. Examples of natural fibers include kenaf fiber, hemp fiber, bamboo fiber, jute fiber, natural cellulose fiber, and wood flour.

  A sizing agent may also be used to converge the fibers. Furthermore, the fiber may be previously treated with a surface treatment agent such as a silane coupling agent. In the present invention, known average fiber length, average fiber diameter, number of filament bundles, etc. in the fiber reinforced propylene resin composition can be used.

  There is no restriction | limiting in particular in the compounding quantity of said filler, A normal compounding quantity can be applied as it is. For example, assuming that the total mass of the polyolefin-based resin and the filler is 100%, the blending amount of the filler is about 2 to 80%, preferably about 5 to 70%. In some cases, about 10 to 60% is more preferable.

  In the present invention, any additive or compounding component conventionally added to polyolefin resins, for example, antioxidants, heat stabilizers, antistatic agents, flame retardants, dispersants, UV absorbers, lubricants, nucleating agents, A mold release agent, a colorant, an alkali metal compound, an ultrahigh molecular weight component, a light stabilizer, a plasticizer, a foaming agent, and the like can be further blended. These blending amounts are not particularly limited as long as they are usually used, and are about 0 to 10%, where the total mass of the polyolefin resin and the filler is 100%.

In the filler-reinforced polyolefin resin composition of the present invention, the remainder of the blending amount of each component is a polyolefin resin.
One preferred filler-reinforced polyolefin resin composition of the present invention contains the modified polypropylene of the present invention in an amount of 0.1 to 2.5%, with the total mass of the polyolefin resin and filler being 100%, and The volatile organic compound is 10 μg / g or less, preferably 3 μg / g or less, more preferably 1 μg / g or less, or the detection limit or less, and the filler is a fiber.
The filler-reinforced polyolefin resin composition of the present invention can be formed into a molded article according to a conventionally known method such as injection molding, extrusion molding or blow molding.

Hereinafter, the present invention will be described in more detail with reference to Examples, Reference Examples and Comparative Examples.
These are examples for explaining the present invention in more detail, and are not limited to these examples.
In addition, including an Example, the maleic anhydride graft amount in this specification, an unreacted acid content, a melt flow rate, and total VOC are the values measured or calculated by the method described below.

Measurement of maleic anhydride graft amount In order to completely remove unreacted acid contained in the maleic anhydride-modified polypropylene of the sample, the acid-modified polypropylene was completely dissolved in a large amount of xylene at 140 ° C. Precipitation and filtration were performed, and the resulting precipitate was heated and dried in vacuum at 140 ° C. and 15 mmHg for 1 hour. This was hot-pressed at 120 ° C. and 200 kgf / cm ² for 1 minute to prepare a film having a thickness of 100 μm. The infrared absorption spectrum of this prepared film was measured, and the amount of maleic anhydride grafted was quantified from the absorption near 1780 cm ⁻¹ .

Measurement of unreacted acid content A sample of maleic anhydride-modified polypropylene was held at 200 kgf / cm ² for 5 minutes by a 140 ° C. heating press to prepare a film having a thickness of 100 μm. In order to avoid water absorption of the prepared film, an infrared absorption spectrum was measured immediately after molding, and the amount of maleic anhydride in the sample was quantified based on absorption near 1780 cm ⁻¹ . The difference from the amount of maleic anhydride grafted after the above purification treatment was defined as the unreacted acid content.

Measurement of Melt Flow Rate Based on JIS-K7210, it was measured at a temperature of 230 ° C. and a load of 21.18N.

Measurement of total VOC Using headspace gas chromatography, 0.1 g of maleic anhydride-modified polypropylene as a sample is taken and placed in a 20 ml vial, and volatile organic components after heating for 1 hour at 80 ° C. are quantified. It was set as VOC.

Example 1
Synthesis of maleic anhydride-modified polypropylene A (modified polypropylene of the present invention) In a 2 L flask equipped with a cooling tube, 750 ml of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate as a solvent, 250 g of powdered polypropylene (propylene) Homopolymer, average particle size of about 0.4 mm, melt flow rate: 2 g / 10 min, melt flow rate value measured at a temperature of 230 ° C. and a load of 21.18 N according to JIS-K7210), anhydrous 180 g of maleic acid and 40 g of tertiary butyl peroxy 2-ethylhexyl carbonate were added and heated to 150 ° C. and stirred for 20 minutes to conduct graft polymerization. An oil bath was used for heating. In order to remove unreacted maleic anhydride from the obtained maleic anhydride-modified polypropylene, it was suspended in 1 L of methyl ethyl ketone, stirred for 30 minutes, and then filtered. After this operation was repeated 4 times, vacuum drying was performed at 120 ° C. and 20 mmHg or less for 2 hours to obtain a maleic anhydride-modified polypropylene of the present invention. The obtained maleic anhydride-modified polypropylene had a graft amount of 2.2% and a melt flow rate of 650 g / 10 minutes.

Comparison of maleic anhydride-modified polypropylene of the present invention with conventional products The modified polypropylene of the present invention was synthesized from the following two types of commercially available maleic anhydride-modified polypropylene (B and C) and maleic anhydride synthesized by the conventional solvent method described below. The modified polypropylene (D), maleic anhydride graft amount, melt flow rate, ratio of unreacted acid to grafted maleic anhydride amount and total VOC were compared, and the results are shown in Table 1 below.

Sample for comparison Maleic anhydride-modified polypropylene B: Maleic anhydride-modified polypropylene OREVAC CA100 (trade name) (manufactured by Arkema, graft amount: 0.6%, melt flow rate: 1000 g / 10 min or more)
Maleic anhydride-modified polypropylene C: Yumex 1001 (trade name, manufactured by Sanyo Chemical Co., Ltd.) (graft amount: 1.7%, melt flow rate: 1000 g / 10 min or more)

Maleic anhydride-modified polypropylene D: synthesized by the method shown in the following reference example.
Reference Example Synthesis of maleic anhydride-modified polypropylene D for comparison In a 1000 ml flask equipped with a cooling tube, 400 ml of xylene as a solvent, 60 g of granular polypropylene (homopolymer, melt flow rate: 2 g / 10 min, melt flow rate value is JIS -Measured according to K7210 at a temperature of 230 ° C. and a load of 21.18 N.) 11.3 g of maleic anhydride was added, heated to 140 ° C. and stirred to dissolve polypropylene, and then dicumyl in 40 ml of xylene. A xylene solution in which 4.1 g of peroxide was dissolved was dropped over 1 hour. After completion of the dropwise addition, the reaction was continued at 140 ° C. for 6 hours. An oil bath was used for heating. After completion of the reaction, the content was lowered to room temperature and poured into acetone to precipitate the target maleic anhydride-modified polypropylene and filtered. In order to remove unreacted maleic anhydride from the obtained maleic anhydride-modified polypropylene, it was put into 500 ml of methyl ethyl ketone, stirred for 10 minutes, and then filtered. This operation was repeated twice, followed by vacuum drying at 120 ° C. and 10 mmHg or less for 2 hours to obtain a maleic anhydride-modified polypropylene D for comparison. The graft amount of the maleic anhydride-modified polypropylene obtained by this operation was 3.5% by mass, and the melt flow rate was 1000 g / 10 min or more.

  A comparison of the present invention and a comparative maleic anhydride modified polypropylene is shown in Table 1 below.

  As can be seen from Table 1, both Comparative Examples 1 and 2, which have been commercially available, have a low graft amount and a melt flow rate as high as 1000 g / 10 min. VOC is also high. For comparison, Comparative 3 (maleic anhydride-modified polypropylene D) synthesized by the conventional solvent method has a high graft amount and a small amount of unreacted acid, but the melt flow rate is also high at 1000 g / 10 min or more. In addition, the total VOC is also high.

Next, an Example and a test example are shown about the filler reinforcement | strengthening polyolefin resin composition of this invention.
In addition, the glass fiber, wood powder, and propylene polymer which were used by the present Example and the comparative example used the following.
Short glass fiber: Fiber diameter 10 μm, fiber length 3.1 mm, manufactured by Asahi Fiber Glass Co., Ltd.
Wood flour: Cellulosin No. 100 (product name), manufactured by Casino Co., Ltd.
Propylene polymer: Novatec ^RTM PP BC06C (trade name), manufactured by Nippon Polypro Co., Ltd., melt flow rate: 60 g / 10 min.

Examples 2, 3 and 4
The maleic anhydride-modified polypropylene A, propylene polymer and glass fiber are supplied to a biaxial co-rotating kneading extruder at the ratio shown in Table 2 below, and the glass fiber reinforced polypropylene resin composition of the present invention is formed into pellets. Obtained.
In addition, the addition amount of maleic anhydride-modified polypropylene A is a ratio relative to the total amount of the propylene polymer and glass fiber as 100%.
Example 2 has a compounding ratio of 0.3%, Example 3 has a compounding ratio of 0.6%, and Example 4 has a compounding ratio of 0.9%.
The graft ratio (%) relative to the total amount of the resin composition shown in the table is the ratio (mass%) of grafted maleic anhydride to the total amount (mass) of glass fiber, propylene polymer and maleic anhydride-modified polypropylene. . Example 2 is 0.006%, Example 3 is 0.012%, and Example 4 is 0.018%.
Moreover, the said extruder model and its operating conditions are as follows.
Model: Belstolf ZE40A (screw length: 1340mm, L / D = 33.5, dice: φ3mm x 5)
Operating conditions: screw rotation speed: 150 rpm, head temperature: 190 ° C., polypropylene supply rate: 21.0 kg / h, glass fiber supply rate: 6.0 kg / h, resin pressure: 1.3 to 1.4 MPa

Comparative Examples 1-5
In the same manner as in Example 2, maleic anhydride-modified polypropylene B to D, propylene polymer, and glass fiber were supplied to a biaxial co-rotating kneading extruder at the ratio shown in Table 3 below, and glass fiber reinforcement for comparison was used. A polypropylene resin composition was obtained in the form of pellets. The blending ratio of the maleic anhydride-modified polypropylenes B to D is the ratio relative to the total amount of the propylene polymer and the glass fiber as 100% in the same manner as in the above examples, and the graft ratio (%) to the total amount of the resin composition Is the ratio (mass%) of grafted maleic anhydride to the total amount (mass) of glass fiber, propylene polymer and maleic anhydride modified polypropylene.

Test example 1
(I) Preparation of Test Specimens The resin composition pellets of the present invention obtained in Examples 2 to 4 above and the comparative resin composition pellets obtained in Comparative Examples 1 to 5 were used as F85 manufactured by Crockner. A JIS-K7139 multipurpose test piece was prepared using an injection molding machine.
(II) Test method Using each of the multipurpose test pieces obtained above, the following properties were applied to the following items, and the respective physical property values were measured.
(1) Tensile strength: Measured according to JIS-K7113.
(2) Flexural modulus: measured according to JIS-K7171.
(3) Charpy impact strength: Measured according to JIS-K7110.
(4) Fatigue strength: In accordance with the cantilever bending fatigue test method ASTM D671, measurement was performed under the following conditions, and evaluation was performed by the number of repetitions until breakage.
Test piece shape: TYPE A, test temperature: 80 ° C., repetition rate: 30 Hz, load stress: 20 MPa
The (1) tensile strength, (2) flexural modulus, and (3) Charpy impact strength measured by the above test are shown in Table 4 below, and (4) fatigue strength is shown in Table 5 below.

Examples 5-8
The maleic anhydride-modified polypropylene A, the propylene polymer, and the wood flour are supplied to the biaxial and co-rotating kneading extruder at the ratio shown in Table 6 below, and the wood flour-filled polypropylene resin composition of the present invention is bulked. Obtained.
In addition, the addition amount of maleic anhydride-modified polypropylene A is a ratio relative to the total amount of the propylene polymer and the wood flour as 100%. A blending ratio of 0.7% is Example 5, a blending ratio of 1.0% is Example 6, a blending ratio of 1.5% is Example 7, and a blending ratio is 2.0%. This is Example 8.
The graft ratio (%) relative to the total amount of the resin composition shown in the table is the ratio (mass%) of grafted maleic anhydride to the total amount (mass) of wood flour, propylene polymer and maleic anhydride-modified polypropylene. . Example 5 is 0.015%, Example 6 is 0.022%, Example 7 is 0.033%, and Example 8 is 0.044%.
Moreover, the said extruder model and its operating conditions are as follows.
Model: Belstolf ZE40A (screw length: 1340mm, L / D = 33.5, dice: φ3mm x 5)
Operating conditions: Screw rotation speed: 150 rpm, head temperature: 190 ° C., supply amount of polypropylene and wood flour: 21.0 kg / h each.

Comparative Examples 6-11
In the same manner as in Examples 5 to 8, maleic anhydride-modified polypropylene B to D, propylene polymer and wood flour were supplied to a biaxial co-rotating kneading extruder at the ratio shown in Table 7 below for comparison. A wood powder-filled polypropylene resin composition was obtained in bulk.
The blending ratio of maleic anhydride-modified polypropylenes B to D is the ratio relative to the total amount of the propylene polymer and wood flour as 100%, as in Examples 5 to 8. The graft ratio (%) relative to the total amount of the resin composition shown in the table is the ratio (mass%) of grafted maleic anhydride to the total quantity (mass) of wood flour, propylene polymer and maleic anhydride-modified polypropylene.

Test example 2
(I) Preparation of test piece 30-40 after heat-pressing the resin composition of this invention obtained in the said Examples 5-8 and the resin composition for comparison obtained in Comparative Examples 6-11 at 180 degreeC. The plate was cooled and pressed at a temperature of 220.times.220.times.4 mm. From this flat plate, various physical property test specimens (JIS K7139 multipurpose test specimens) were cut out using a lathe.
(II) Test Method Using the test pieces obtained above, the following physical properties were measured according to the following methods.
(1) Tensile strength: Measured according to JIS-K7113.
(2) Flexural strength and flexural modulus: measured according to JIS-K7171.
(3) Charpy impact strength: Measured according to JIS-K7110.
Table 1 below shows (1) tensile strength, (2) flexural strength / flexural modulus, and (3) Charpy impact strength measured as described above.

As apparent from Table 4 and Table 5, for the glass fiber reinforced polypropylene resin compositions of Examples 2 to 4 of the present invention, the value of Example 2 is the value of Comparative Example 2 in the Charpy impact test with notch. Except for the lower limit, the tensile yield stress, the flexural modulus, the Charpy impact value, and the cantilever bending fatigue test were all superior to Comparative Examples 1 to 4. Further, as apparent from Table 8 above, the wood powder-filled polypropylene resin compositions of Examples 5 to 8 of the present invention are comparative examples for any of the tensile yield stress, bending strength, bending elastic modulus and Charpy impact value. Excellent values were shown for 6-11.
From the above results, by blending the maleic anhydride-modified polypropylene of the present invention with a filler-reinforced polyolefin resin composition, mechanical strength and durability such as tensile strength, bending strength, flexural modulus, impact strength and fatigue strength are obtained. It can be seen that a filler-reinforced polyolefin resin composition having excellent properties can be obtained.

Claims (6)

Maleic anhydride-modified polypropylene having a maleic anhydride grafting amount of 1.8 to 2.5% by mass and a melt flow rate (MFR) of 600 g / 10 min or more and 700 g / 10 min or less, provided that maleic anhydride is used. graft amount of, and the measured values in the following manner.
Measurement of grafting amount of maleic anhydride:
Maleic anhydride-modified polypropylene is completely dissolved in 140 ° C. xylene, cooled, precipitated with acetone and filtered, and the resulting precipitate is heated and vacuum dried at 140 ° C. and 15 mmHg for 1 hour. Was heated at 120 ° C. and 200 kgf / cm ² for 1 minute to prepare a film having a thickness of 100 μm, and an infrared absorption spectrum of the prepared film was measured. The amount of maleic anhydride grafted was determined by absorption at 1780 cm ^−1. Quantify.   The non-grafted maleic anhydride (including maleic anhydride oligomer) content in the maleic anhydride-modified polypropylene is 25% by mass or less based on 100% by mass of the grafted maleic anhydride. Maleic acid modified polypropylene.   A filler-reinforced polyolefin resin composition comprising the maleic anhydride-modified polypropylene according to claim 1.   The filler-reinforced polyolefin resin composition according to claim 3, wherein the content of maleic anhydride-modified polypropylene is 0.01 to 3% by mass relative to the total amount of the filler and the polyolefin resin.   The filler-reinforced polyolefin resin composition according to claim 3 or 4, wherein the filler is fibers.   The filler-reinforced polyolefin resin composition according to claim 5, wherein the fibers are selected from the group consisting of glass fibers, carbon fibers, and natural fibers.