JP7431436B2 - Flame-retardant polypropylene resin composition - Google Patents

Description

The present invention relates to a novel flame-retardant polypropylene resin composition.

Polypropylene resin is a typical example of polyolefin resin. In addition to being light and strong, polypropylene resin has good water resistance, chemical resistance, electrical insulation, etc., and is also easy to mold. be. For this reason, they are widely used in, for example, building materials, electrical equipment materials, vehicle parts, automobile interior materials, wire covering materials, and various other industrial products and household products. However, polypropylene resin has the drawback of being highly flammable. For this reason, various methods have been proposed for making polyolefin flame retardant.

A common method for making synthetic resin flame retardant is to add a flame retardant to the resin. Among the conventional methods for flame retardation, the most used example is the addition of halogen-based organic compounds, antimony-based compounds, etc. Examples of the halogenated organic compounds include tetrabromobisphenol A, hexabromocyclododecane, bisdibromopropyl ether of tetrabromobisphenol A, bisdibromopropyl ether of tetrabromobisphenol S, tris 2,3-dibromopropylisocyanurate, and bisdibromopropyl ether of tetrabromobisphenol A. Pentabromophenylethane, hexabromobenzene, decabromo biphenyl ether, etc. are known. Examples of the antimony-based compound include antimony oxide and the like.

However, in recent years, due to increasing global environmental awareness, there has been a strong demand for refraining from using halogen-based organic compounds, which tend to generate harmful gases (hydrogen bromide, etc.) when burned. Among antimony-based compounds, antimony oxide (diatimony trioxide), which is particularly excellent in cost and performance, is becoming increasingly regulated, such as being designated as a specified chemical substance under the Industrial Safety and Health Act, making it difficult to use.

In view of the current situation, several methods have been proposed for imparting flame retardancy to synthetic resins without using halogen flame retardants. One of them is the addition of metal hydroxides such as aluminum hydroxide and magnesium. However, the flame retardant mechanism of metal hydroxides is obtained by water generated by heating, and the flame retardant effect is low, and a large amount of metal hydroxide must be added in order to obtain the desired flame retardant effect. Addition of a large amount of metal hydroxide may significantly impair the physical properties, processability, etc. inherent to the resin. Furthermore, since the dehydration reaction of metal hydroxides occurs gradually at temperatures above 200°C, there are problems such as generation of water during kneading into synthetic resins, and the applications for which they can be used are limited.

As another method that does not use halogenated flame retardants, many proposals have been made to use phosphates such as ammonium polyphosphate. However, when a large amount of this type of phosphate is added, although sufficient flame retardance can be ensured, the moisture resistance is poor and a hydrolysis reaction occurs due to water absorption. For this reason, for example, in a high temperature and high humidity environment, the appearance of the molded product and the physical properties of the resin deteriorate significantly. In addition, phosphates may bleed out onto the surface of a resin molded product made of this flame retardant composition, causing a number of blooming phenomena.

In order to improve the above-mentioned drawbacks, we have developed melamine resin cross-linked types, phenol resin cross-linked types, epoxy cross-linked types with particularly improved moisture resistance, or coated ammonium polyphosphates whose surface has been treated with a silane coupling agent, silicone oil, etc. Proposed. (Patent Documents 1 to 4) However, this method has drawbacks such as poor resin compatibility or dispersibility and reduced mechanical strength. Furthermore, the coating may peel off due to heat or stress during resin kneading.

Generally, resin compositions containing ammonium polyphosphate undergo thermal decomposition due to thermal separation of ammonia gas when the temperature exceeds 200°C during kneading, so thermally decomposed products bleed out even during kneading, resulting in damage to the strands. Causes water wetting. This causes extremely poor physical properties and productivity of the flame-retardant resin composition.

It is also known to use organic phosphoric acid esters such as triphenyl phosphate and tricresyl phosphate as flame retardants. However, these cannot be added in large amounts because they do not have sufficient flame retardant performance, and when used in nonpolar resins such as polyolefins, they tend to bleed out and significantly impair the appearance of the resin surface. In addition, organic phosphoric acid esters may gradually cause a hydrolysis reaction with moisture in the air, producing phosphoric acid. If phosphoric acid is produced in a synthetic resin, it may lower the molecular weight of the synthetic resin, and if used in electrical or electronic parts, it may cause short circuits. These organic phosphate esters have low heat resistance and are easily thermally decomposed, and many of them are volatile, so they decompose and volatilize during granulation and molding of flame-retardant resins, making them difficult to process. It can lead to extreme sexual deterioration.

On the other hand, flame-retardant resins using organic phosphonic acid compounds are also being studied, and there are reports that flame-retardant properties can be imparted to resins using composite materials such as organic nitrogen compounds such as melamine and silicon compounds (patented). Reference 5). However, in order to achieve V-0, a blending ratio of 30% or more is required, which has a large effect on the physical properties of the resin and is not economically viable, so it is not practical.

Additionally, hindered amine nitrogen compounds (NOR-HALS) have been proposed as radical trapping non-halo/nonphosphorus flame retardants, and it has been confirmed that their radical trapping ability is enhanced when combined with some phosphonic acid esters. (Non-patent Document 6). However, when NOR-HALS is used, although it is very effective for thin objects such as sheets, films, and fibers, it is less effective for molded objects, and its applications are limited.

Japanese Patent Application Publication No. 8-183876 Special Publication No. 6-18944 Japanese Patent Application Publication No. 8-134455 Japanese Patent Application Publication No. 2007-231183 Special Publication No. 2008-628723

“Latest technology of flame retardant + flame retardant technology” (CMC Publishing, 2015, p. 113-114)

In this way, in the conventional technology, if another flame retardant component is used to achieve flame retardancy without using a halogen compound or an antimony compound as a flame retardant component, a large amount of other flame retardant component must be added, and as a result, the original performance of the resin is deteriorated. The reality is that damage or bleed-out problems are unavoidable.

Therefore, the main object of the present invention is to create a polypropylene resin composition that effectively maintains the original physical properties of polypropylene resin while exhibiting excellent flame retardancy and bleed resistance without relying on halogen compounds and antimony compounds. It's about providing things.

The present inventor has discovered that the above object can be achieved by applying specific components in specific proportions to a polypropylene resin, and has completed the present invention.

That is, the present invention relates to the following flame-retardant polypropylene resin composition.
1. Ingredients below:
(1) Polypropylene resin: 64.5 to 96.5% by weight,
(2) General formula below
(In the formula, R is an alkyl group having 4 to 8 carbon atoms which may have a substituent, a phenyl group which may have a substituent, or a benzyl group which may have a substituent) _R2 represents an optionally substituted amino group or an optionally substituted phenyl group. x and y satisfy 0.5≦x/y≦2.5 .)
Phosphonic acid amine salt represented by: 3.0 to 30.0% by weight,
(3) NOR hindered amine compound: 0.25 to 2.5% by weight,
(4) General formula below
(In the formula, n represents an integer of 1 or 2.)
Phosphonic acid ester compound represented by: 0 to 3.0% by weight
A flame-retardant polypropylene resin composition containing.
2. 2. The flame-retardant polypropylene resin composition according to item 1, further comprising 0.01 to 0.1% by weight of at least one of an antioxidant and a heat stabilizer.
3. 3. The flame-retardant polypropylene resin composition according to item 1 or 2, wherein the total content of the halogen compound and the antimony compound is 10% by weight or less.
4. 4. The flame-retardant polypropylene resin composition according to any one of items 1 to 3 above, wherein the phosphonic acid amine salt is at least one of melamine butylphosphonate and benzoguanamine butylphosphonate.
5. A molded article obtained by molding the flame-retardant polypropylene resin composition according to any one of items 1 to 4 above.

According to the present invention, there is provided a polypropylene resin composition that exhibits excellent flame retardancy and bleed resistance without relying on halogen compounds and antimony compounds, while effectively maintaining the physical properties inherent to the polypropylene resin. can do.

Polypropylene resin compositions and molded products thereof having these characteristics are used in various industries, including products that require flame retardancy and bleed resistance, such as automobile interior materials, housings for home appliances, and wire coating materials. It can be widely used for supplies, daily necessities, etc.

1. Flame-retardant polypropylene resin composition The flame-retardant polypropylene resin composition of the present invention (composition of the present invention) contains the following components:
(1) Polypropylene resin: 64.5 to 96.5% by weight,
(2) General formula below
(In the formula, R is an alkyl group having 4 to 8 carbon atoms which may have a substituent, a phenyl group which may have a substituent, or a benzyl group which may have a substituent) _R2 represents an optionally substituted amino group or an optionally substituted phenyl group. x and y satisfy 0.5≦x/y≦2.5 .)
Phosphonic acid amine salt represented by: 3.0 to 30.0% by weight,
(3) NOR hindered amine compound: 0.25 to 2.5% by weight,
(4) General formula below
(In the formula, n represents an integer of 1 or 2.)
Phosphonic acid ester compound represented by: 0 to 3.0% by weight
It is characterized by including. Each component constituting the composition of the present invention will be explained below.

Polypropylene Resin The polypropylene resin may be one containing [-CH(CH ₃ ) CH ₂ -] as a monomer, and may be either a homopolymer or a copolymer. Alternatively, a polymer alloy containing polypropylene resin may be used. Known or commercially available polypropylene resins can also be used. These can be used alone or in combination of two or more.

Further, when the polypropylene resin is a homopolymer, it may be isotactic, atactic or syndiotactic.

When the polypropylene resin is a copolymer, the other monomers are not limited as long as they do not interfere with the effects of the present invention, and examples include at least one of ethylene, butene, hexene, octene, and the like. Although the content of other monomers depends on the type of monomer used, it is usually preferably 40 mol% or less (particularly 30 mol% or less). Therefore, it can be set to 1 to 25 mol%, for example.

Furthermore, the polypropylene resin may be a polymer alloy containing a polypropylene resin. For example, at least one of polyamide, polylactic acid, polyester, polyacrylate, ethylene propylene rubber, polystyrene, etc. can be mentioned. The content of polypropylene in the case of a polymer alloy can be set to, for example, 60 to 90% by weight, but is not limited thereto.

The weight average molecular weight of the polypropylene resin may be, for example, within a range of about 100,000 to 1,500,000, but is not limited thereto.

The MFR (JIS K7210, measurement temperature 230° C.) of the polypropylene resin is not limited, but is usually in the range of about 0.5 to 100 g/10 min, particularly preferably 5 to 30 g/10 min.

The content of the polypropylene resin in the composition of the present invention is not particularly limited, but can usually be set appropriately within the range of 64.5 to 96.5% by weight. Therefore, it can be within the range of 75 to 95% by weight, for example.

The composition of the present invention may contain resin components other than polypropylene resins (for example, polyamide, polylactic acid, polyester, polyacrylate, ethylene propylene rubber, polystyrene, etc.) within a range that does not impede the effects of the present invention. . In this case, the content of the resin component may be set so that the content of the polypropylene resin falls within the above range.

Phosphonic acid amine salt Phosphonic acid amine salt has the following general formula:
(In the formula, R is an alkyl group having 4 to 8 carbon atoms (especially 4 to 6 carbon atoms) which may have a substituent, a phenyl group which may have a substituent, or a phenyl group having a substituent. _R2 represents an optionally substituted amino group or a optionally substituted phenyl group. x and y are 0.5≦x /y≦2.5) is used. These can be used alone or in combination of two or more.

The above R is particularly preferably a benzyl group or an alkyl group having 4 to 8 carbon atoms (preferably 4 to 6 carbon atoms) (ie, butyl group, pentyl group, or hexyl group). In particular, alkyl groups with 3 or less carbon atoms are highly hydrophilic, so when kneaded into polypropylene resin, bleed-out occurs as a liquid substance (thick aqueous solution) on the resin surface under high temperature and high humidity conditions. Therefore, the appearance and flame retardancy may be reduced. When the number of carbon atoms is 9 or more, a large amount must be added in order to obtain the desired flame retardancy, which may deteriorate the original properties of the resin or be economically disadvantageous.

The above R ₂ is particularly preferably an amino group or a phenyl group. Among them, amino group is more preferable. That is, it is preferable that the compound y is melamine.

The above-mentioned substituents are not particularly limited, and include, for example, nitrogen-based substituents such as amino groups, amido groups, and nitro groups, sulfur-based substituents such as sulfonic acid groups, and carbon-based substituents such as carboxyl groups and alkoxy groups. etc. Each substituent may be the same or different from each other.

The above x and y preferably satisfy 0.5≦x/y≦2.5, particularly 1.0≦x/y≦2.0. If x/y is less than 0.5, the amount of free melamine increases and the heat resistance during kneading decreases, which is not preferable. Furthermore, when x/y exceeds 2.5, the pH of the crystalline salt becomes low, which is undesirable because it causes problems of corrosion of the kneader and the like.

The above-mentioned amine salt of phosphonic acid is a powdery salt produced by neutralizing phosphonic acid, which is normally easily soluble in water, with an amine compound, and has the property of being difficult to dissolve in water. That is, one of the features of the present invention is that phosphonic acid, which is easily soluble in water, is used by changing its properties to be less soluble in water. However, if the phosphonic acid is kneaded into a polypropylene resin (particularly a melt of polypropylene resin) as it is, it will be difficult to mix and will easily bleed from the resin. Furthermore, since phosphonic acid itself is strongly acidic, there is a concern that it may cause corrosion of the kneading machine. On the other hand, the above-mentioned amine salt has lower polarity than free phosphonic acid, so it easily mixes with polypropylene resin (particularly a melt of polypropylene resin) and is less likely to bleed. As a result, high flame retardancy can also be imparted by the above-mentioned amine salt of phosphonic acid.

The above-mentioned amine salt of phosphonic acid is not particularly limited as long as it can be obtained by reacting a phosphonic acid compound and an amine compound in a predetermined ratio.

The phosphonic acid compound is not limited, and known or commercially available ones can also be used. Moreover, compounds synthesized according to known production methods can also be used. For example, alkylphosphonic acid (butylphosphonic acid, etc.) obtained by the production method described in International Publication WO 2016/152747 can be suitably used.

The amine compound is not particularly limited as long as it satisfies the following formula.
The above R ₂ represents an optionally substituted amino group or a optionally substituted phenyl group. Examples of the substituent include a methyl group, an ethyl group, and a propyl group. Specific examples of amine compounds include melamine, benzoguanamine, and the like. Known or commercially available ones can also be used.

The reaction between the phosphonic acid compound and the amine compound includes, for example, a step of neutralizing the phosphonic acid compound and the amine compound in an aqueous solvent (neutralization reaction step) and a step of precipitating crystals from the reaction system (crystal precipitation step). It can be carried out by a method including.

In the neutralization reaction step, a phosphonic acid compound and an amine compound are subjected to a neutralization reaction in an aqueous solvent.

Water-based solvents include water, methanol, and ethanol. In addition to alcohols such as isopropyl alcohol (IPA), aprotic polar solvents such as acetone, ethyl acetate, tetrahydrofuran (THF), and dimethylformamide (DMF) can be suitably used. These can be used alone or in a mixture of two.

The reaction temperature for the neutralization reaction is not particularly limited, but it is preferably heated at about 80 to 100°C from the viewpoint of more reliably dissolving the phosphonic acid compound and the amine compound in water. Further, the reaction time is not limited, but it is usually about 15 to 30 minutes.

The neutralization molar ratio in this step is not particularly limited, but is usually in the same range as x/y above. That is, it is desirable that the phosphonic acid compound:amine compound=0.5:1.0 to 2.5:1.0, particularly the phosphonic acid compound:amine compound=1.0:1.0 to 2.0: It is more desirable to set it to 1.0.

In the crystal precipitation step, crystals are precipitated from the reaction system. The method for precipitating the crystals is not particularly limited, and for example, when the reaction system is under heating, a step of cooling the reaction system can be employed. As a result, the above-mentioned amine salt of phosphonic acid is precipitated in the reaction solution. In the case of cooling, the reaction system (reaction liquid) is usually cooled to below room temperature (for example, about 5 to 30°C). The crystals thus obtained can be obtained in the form of powder through solid-liquid separation (filtration, centrifugation, etc.), drying treatment, pulverization treatment, classification treatment, etc., as required.

The content of the amine salt of phosphonic acid in the composition of the present invention is preferably 3.0 to 30.0% by weight, particularly 5.0 to 20.0% by weight. If the content is less than 3.0% by weight, the desired flame retardance cannot be obtained. On the other hand, if the content exceeds 30.0% by weight, not only will economic efficiency be impaired, but also the physical properties of the resin will be significantly reduced.

NOR-based hindered amine compounds NOR-based hindered amine compounds are hindered amine compounds (HALS) that have a -N-OR (R represents a hydrocarbon group) structure in the molecule, and are generally known as light stabilizers. This is a compound that is known or commercially available.

Commercially available products include, for example, "Flamestab NOR-116FF" manufactured by BASF, "Tinvin NOR-371FF" manufactured by BASF, "Tinvin 123" manufactured by BASF, "Tinvin 152" manufactured by BASF, and "ADK STAB LA-" manufactured by ADEKA Corporation. 81'' etc. These can be used alone or in combination of two or more.

The content of the NOR hindered amine compound in the composition of the present invention is preferably 0.25 to 2.5% by weight, particularly 0.50 to 1.50% by weight. If the content is less than 0.25% by weight, the desired flame retardance cannot be obtained. When the above content exceeds 2.5% by weight, desired flame retardancy can be obtained, but it is disadvantageous in terms of cost.

Phosphonate ester compound The phosphonate ester compound has the following general formula:
(In the formula, n represents an integer of 1 or 2.)
A phosphonic acid ester compound represented by is used. These can be used alone or in combination of two or more. In the composition of the present invention, the phosphonic acid ester compound is not essential, but by using it, the amount of the NOR hindered amine compound can be reduced while maintaining the desired flame retardancy. Browning that may occur due to the addition of a hindered amine compound can be more reliably suppressed. At the same time, the amount of the relatively expensive NOR hindered amine compound used can be reduced, so economical benefits can be obtained accordingly.

The above-mentioned phosphonic acid ester is known as a flame retardant component, and commercially available ones can also be used. Examples of commercially available products include "Nonne 73" and "Nonne 75" manufactured by Marubishi Yuka Kogyo Co., Ltd.

The content of the phosphonic acid ester compound can be about 0 to 3.0% by weight in the composition of the present invention, but from the economical point of view as mentioned above, it is set to 0.5 to 2.0% by weight. It is preferable.

Other components The composition of the present invention may contain other components (excluding the above components (1) to (4) of the composition of the present invention) within a range that does not impede the effects of the present invention. Also good. For example, additives blended into known or commercially available resin compositions can be used.

More specifically, for example, 1) antioxidants such as phenolic compounds, phosphine compounds, and thioether compounds; 2) ultraviolet absorbers such as benzophenone compounds, benzotriazole compounds, salicylate compounds, and hindered amine compounds. or light resistance agent, 3) antistatic agent and conductive agent such as cationic compound, anionic compound, nonionic compound, amphoteric compound, metal oxide, π-based conductive polymer compound, carbon, 4) fatty acid, fatty acid amide, lubricants such as fatty acid esters and fatty acid metal salts; 5) nucleating agents such as benzylidene sorbitol compounds; 6) talc, calcium carbonate, barium sulfate, mica, glass fibers, glass beads, and metal hydroxides (which inhibit flame retardancy). 7) In addition, flame retardants, heat stabilizers (especially phosphorus heat stabilizers), metal deactivators, and colorants. Agents, antiblooming agents, surface modifiers, antiblocking agents, antifogging agents, adhesives, gas adsorbents, deodorants, fragrances, physical property modifiers (elastomers, etc.), and the like. These can be used alone or in combination of two or more. When these various additives are blended, the content of the additives in the composition of the present invention can be, for example, about 0.1 to 20% by weight, but is not limited thereto.

Further, it is most preferable that the composition of the present invention does not contain a halogen compound and an antimony compound, but it is permissible for them to be contained within a range that does not impede the effects of the present invention. For example, the total content of halogen compounds and antimony compounds is preferably 10% by weight or less, particularly preferably 0 to 0.1% by weight.

2. Method for producing the composition of the present invention The method for producing the composition of the present invention is not particularly limited as long as the components described in "1. Flame-retardant polypropylene resin composition" above can be mixed uniformly. For example, the composition of the present invention can be obtained by uniformly mixing each component in a predetermined ratio by dry blending. In this case, the composition of the present invention can be obtained as a powder composition.

In particular, the molded article of the present invention as described below can also be directly produced from each component. In this case, for example, 1) a step of preparing a melt of polypropylene resin; 2) obtaining a molten mixture by adding at least the phosphonic acid amine salt, the NOR hindered amine compound, and the phosphonic acid ester to the melt; A method including steps can be suitably employed. Thereby, a molded article formed by molding the molten mixture into a desired shape can be efficiently obtained.

3. Molded object of the composition of the present invention The present invention also includes a molded object formed by molding the composition of the present invention. The molding method is not particularly limited, and various methods such as press molding, injection molding, extrusion molding, vacuum molding, and blow molding can be employed.

The molded body can be used for various purposes. It can be suitably used for the same purposes as known polypropylene resin products. For example, it can be widely used in various applications such as electronic equipment, home appliances, OA equipment, daily necessities, medical equipment, building materials, automobile parts, packaging materials, and containers. Among these, the molded article of the present invention can be suitably used in applications that require flame retardancy (for example, home appliances, interior or exterior materials for OA equipment, construction sheets, etc.).

Hereinafter, the present invention will be explained in more detail by giving Examples and Comparative Examples. However, the present invention is not limited to these examples.

A. About the raw materials used (1) Polypropylene resin (1-1) "Prime Polypro J106G" manufactured by Prime Polymer Co., Ltd., MFR: 15.0 g / 10 min, homo-PP (indicated as "J106G" in the table).
(1-2) "Prime Polypro J226T" manufactured by Prime Polymer Co., Ltd., MFR: 20.0g/10min, rad-PP (written as "J226T" in the table).
(1-3) "Prime Polypro J707G" manufactured by Prime Polymer Co., Ltd., MFR: 30.0g/10min, block-PP (written as "J707G" in the table)

(2) Amine salt of phosphonic acid (2-1) Melamine butylphosphonic acid Butylphosphonic acid was prepared according to the method described in Examples 1 to 2 of International Publication WO 2016/152747. Next, the above butylphosphonic acid (12.61 g), melamine (12.61 g) and water (200.0 g) were placed in a 300 ml round bottom flask equipped with a condenser, a stirrer, a thermometer, a dropping funnel with a side tube, and a nitrogen inlet tube. ) was added and stirred while heating to 95°C. After uniformly dissolving at around 90°C, the mixture was cooled to 10°C over 1 hour while stirring to obtain a white slurry. The obtained slurry was filtered under reduced pressure and dried to obtain white powdery butylphosphonate melamine. The yield was 85.5%. The obtained powder was pulverized with a feather mill to prepare a sample for kneading into resin.
(2-2) Octylphosphonic acid melamine In a 300ml round bottom flask equipped with a condenser, stirrer, thermometer, dropping funnel with side tube, and nitrogen introduction tube, put n-octylphosphonic acid (manufactured by Tokyo Kasei Kogyo Co., Ltd.: 29. 13g), melamine (12.61g) and water (200.0g) were added, and the mixture was heated and stirred to 95°C. After uniformly dissolving at around 90°C, the mixture was cooled to 10°C over 1 hour while stirring to obtain a white slurry. The resulting slurry was filtered under reduced pressure and dried to obtain white powdery melamine octylphosphonate. The yield was 82.4%. The obtained powder was pulverized with a feather mill to prepare a sample for kneading into resin.
(2-3) Melamine benzylphosphonate
Trimethyl phosphate (49.64 g) was placed in a 300 ml round bottom flask equipped with a condenser, a stirrer, a thermometer, a dropping funnel with a side tube, and a nitrogen inlet tube, and heated with stirring to bring it to gentle reflux. Benzyl bromide (66.70 g) was added dropwise from the dropping funnel over 1 hour, and reflux was continued for 5 hours to obtain dimethylbenzyl phosphate. Next, the condenser was removed, concentrated sulfuric acid (1.05 g) was added, the mixture was heated to 150° C., and water (100 g) was added dropwise from the dropping funnel over 10 hours. During this time, the internal temperature of the flask was maintained at 150°C. The flask was cooled to room temperature to obtain slightly brown crystalline benzylphosphonic acid (64.2 g). Next, the benzylphosphonic acid (10.00 g), melamine (4.89 g), and water (100.0 g) were placed in a 300 ml round bottom flask equipped with a condenser, stirrer, thermometer, dropping funnel with side tube, and nitrogen inlet tube. ) was added and stirred while heating to 95°C. After uniformly dissolving at around 90°C, the mixture was cooled to 10°C over 1 hour while stirring to obtain a white slurry. The resulting slurry was filtered under reduced pressure and dried to obtain melamine benzylphosphonate in the form of a white powder. The yield was 68.0%. The obtained powder was pulverized with a feather mill to prepare a sample for kneading into resin.
(2-4) Melamine Methylphosphonic Acid In a 300 ml round bottom flask equipped with a condenser, stirrer, thermometer, dropping funnel with side tube, and nitrogen introduction tube, methylphosphonic acid (manufactured by Tokyo Kasei Kogyo Co., Ltd.: 9.60 g), melamine (12.61 g) and water (200.0 g) were added, and the mixture was heated and stirred to 95°C. After uniformly dissolving at around 90°C, the mixture was cooled to 10°C over 1 hour while stirring to obtain a white slurry. The obtained slurry was filtered under reduced pressure and dried to obtain white powdery melamine methylphosphonate. The yield was 39.5%. The obtained powder was pulverized with a feather mill to prepare a sample for kneading into resin.
(2-5) Benzoguanamine butylphosphonic acid Butylphosphonic acid was prepared according to the method described in Examples 1 to 2 of International Publication WO2016/152747. Next, the above butylphosphonic acid (12.61 g), benzoguanamine (17.09 g) and water (200.0 g) were placed in a 300 ml round bottom flask equipped with a condenser, a stirrer, a thermometer, a dropping funnel with a side tube, and a nitrogen inlet tube. ) was added and stirred while heating to 95°C. After stirring at around 90°C for 1 hour, the mixture was cooled to 10°C over 1 hour while stirring to obtain a white slurry. The obtained slurry was filtered under reduced pressure and dried to obtain white powdery benzoguanamine butylphosphonate. The yield was 89.9%. The obtained powder was pulverized with a feather mill to prepare a sample for kneading into resin.

(3) NOR hindered amine compound (3-1) "Flamestab NOR-116FF" manufactured by BASF (indicated as "NOR-116FF" in the table)
(3-2) “Tinvin NOR-371FF” manufactured by BASF (written as “NOR-371FF” in the table)

(4) Phosphonate ester compound (4-1) "Nonnene 73" manufactured by Marubishi Yuka Kogyo Co., Ltd. (melting point: approximately 100°C), phosphonate ester compound (indicated as "Nonnene 73" in the table).

B. About examples and comparative examples
Examples 1 to 12 and Comparative Examples 1 to 5
After weighing each component of A above to have the composition shown in Tables 1 to 3 (unit: "wt%"), using a kneader ("Laboplast Mill C4150" manufactured by Toyo Seiki Co., Ltd.), Polypropylene resin was melt-kneaded at 200°C. 0.05% by weight of a hindered phenolic antioxidant (product name "Irganox 1010" manufactured by BASF Japan) and 0.05% by weight of a phosphorus processing heat stabilizer (product name "Irgafos 168") are added to the melted resin component. was added in the form of a mixture of the two, and then slowly added a mixture of a phosphonate amine salt, a NOR hindered amine compound, and a phosphonate ester compound, and after the addition was completed, the mixture was further kneaded at the same temperature for 5 minutes to prepare a mixture. did. After the kneading was completed, the obtained mixture was press-molded (210° C. x 3 minutes, 100 kgf) to prepare test pieces for each test in Test Example 1 described later. In addition, the above-mentioned hindered phenol antioxidant is written as "Irganox 1010" in the table, and the phosphorus processing heat stabilizer is written as "Irgafos 168".

Test example 1
The test pieces obtained in each Example and Comparative Example were evaluated as follows. The results are also shown in Tables 1 to 3.

(1) Flammability
For evaluation of flame retardancy, 3.0 mm and 1.5 mm thick UL test pieces were prepared and a combustion test was conducted in accordance with the UL94V test method. The results of the UL94V combustion test were evaluated in four stages: "V-0,""V-1,""V-2," and "unacceptable."

(2) Bleed test
After preparing a flat test piece with a thickness of 3 mm, it was heated at 80°C for 7 days, and then the test piece was subjected to an aging treatment for 48 hours at a temperature of 23°C and a humidity of 50% Rh, and the surface of the test piece was visually observed and Wiping with a black cloth was visually observed. The result of the bleed test is ``○'' when no seepage is observed and no white powder adheres to the black cloth after wiping. The case where the stain was removed was marked as "△", and the case where seepage was observed and white powder was seen on the black cloth after wiping was marked as "x".

(3) Humid heat resistance test
After treating a flat test piece with a thickness of 3 mm for 14 days under the high temperature and high humidity conditions of a) a temperature of 60°C and a humidity of 90% Rh, and b) a temperature of 85°C and a humidity of 85% Rh, the test piece was treated at a temperature of 23°C and a humidity of 50% Rh. After aging for 24 hours under conditions of %Rh, oozing of flame retardant etc. from the surface of the test piece was visually checked by wiping with a black cloth. The results of the moisture resistance test are marked as "○" if no transfer material is observed on the black cloth, "△" if some liquid transfer material is observed, and "x" if significant liquid transfer material is observed. did. Note that in each of the Examples and Comparative Examples, the results of a) and b) above were the same, so both are listed together in the "Moisture Heat Resistance Test" section of each table.

As is clear from the results in Tables 1 to 3, the composition of the present invention has superior flame retardance than the comparative example even if it does not contain a halogen compound or an antimony compound. It can be seen that flammability and bleed resistance can be exhibited.

Claims (4)

Ingredients below:
(1) Polypropylene resin: 64.5 to 96.5% by weight,
(2) at least one phosphonic acid amine salt of melamine butylphosphonate and benzoguanamine butylphosphonate : 3.0 to 30.0% by weight;
(3) NOR hindered amine compound: 0.25 to 2.5% by weight,
(4) General formula below
(In the formula, n represents an integer of 1 or 2.)
Phosphonic acid ester compound represented by: 0 to 3.0% by weight
A flame-retardant polypropylene resin composition containing. The flame-retardant polypropylene resin composition according to claim 1, further comprising 0.01 to 0.1% by weight of at least one of an antioxidant and a heat stabilizer. The flame-retardant polypropylene resin composition according to claim 1 or 2, wherein the total content of the halogen compound and the antimony compound is 10% by weight or less. A molded article obtained by molding the flame-retardant polypropylene resin composition according to any one of claims 1 to 3 .