KR920000001B1 - Agricultural multilayer film polymer - Google Patents

Abstract

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Description

Agricultural Multilayer Film

TECHNICAL FIELD The present invention relates to an agricultural multilayer film, and more particularly, to an agricultural multilayer film excellent in heat retention, transparency, and workability of working in a warp.

In recent years, with the modernization of crop cultivation, facility cultivation, such as house cultivation and tunnel cultivation, has become widespread. In the cultivation of these materials, primary coating materials such as plastic houses, tunnels, and secondary coating materials for double interiors such as curtains include polyethylene films, polyvinyl chloride films, ethylene-vinyl acetate copolymer resin films, and various other materials. Among them, soft polyvinyl chloride film has the mainstream of coating materials because of its excellent thermal insulation, transparency, work strength, and price.

However, the polyvinyl chloride film has a problem in the waste treatment itself, such as the generation of halogen-based gas during the waste treatment and low combustibility.

In addition, this film has a problem in long-term use because the surface is generally adhered by a bleeding agent made of a plasticizer, dust and the like adhere to the long-term outdoor use, and the light transmittance is reduced.

On the other hand, in the ethylene-vinyl acetate copolymer resin film replaced therewith, the thermal insulation property and the work strength were inferior to those of the polyvinyl chloride film, and thus there were limitations on the use conditions.

In addition, the use of the polyethylene film has been limited because the heat insulating property and the transparency of the egg-coating are inferior to those of the polyvinyl chloride film.

In order to solve these drawbacks, various methods have recently been proposed to improve the heat retention and workability of ethylene-vinyl acetate copolymer resins.

For example, in order to improve heat retention, silica (JP-A-47-13853, magnesium compound (JP-A 59-226037), hydrotalcite (JP-A 60-104141) are applied to ethylene-vinyl acetate copolymer resin). Addition of fillers, such as the addition of absorbent resin (Japanese Patent Laid-Open No. 61-81446) and ethylene-vinyl alcohol copolymer resin (Japanese Patent Laid-Open No. 55-118941).

In addition, Japanese Laid-Open Patent Publication No. 57-160638 discloses a film in which a polyolefin layer containing an anti-dropping agent and a polyolefin layer containing an organic compound containing a metal are laminated. Disclosed is an agricultural film in which a resin layer containing a base material layer and a surfactant mainly composed of (linear low-density polyethylene, sometimes abbreviated as L-LDPE) is laminated. However, it also turned out that these laminated | multilayer films also do not reach the level of the heat retention improvement calculated | required by the market. In other words, it is difficult to obtain a film that satisfies all of the transparency, the heat retention, the weatherproofness, and the working strength by the conventional means.

MEANS TO SOLVE THE PROBLEM The present inventors addressed this fault, and especially obtained the agricultural multilayer film which was excellent in transparency, heat insulation, abundance property, and work intensity | strength, and as a result of earnestly examining, the film of the specific multilayer structure containing the specific filler and oil-repellent agent in each layer is used Thus, the present inventors have found that the present invention can be achieved, and thus, the present invention has been completed.

That is, according to this invention, the low density polyethylene or vinyl acetate content 20 weight% or less ethylene- which consists of a multilayer film of two layers or three layers or more, and whose one surface layer (A) contains 0.1 to 2 weight% of rainproof agents There is provided an agricultural film, wherein the layer is composed of vinyl acetate copolymer, and at least the other one layer (B) is a layer composed of ethylene-based resin containing 1 to 40% by weight of hydrotalcite or a flexible compound thereof. .

In the present invention, the polymer constituting one surface layer (A) is a low density polyethylene or an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20% by weight or less.

Low density polyethylene refers to polyethylene having a density of less than 0.930 g / cm 3. Such low density polyethylenes are roughly classified into branched low density polyethylenes and linear low density polyethylenes.

Branched low density polyethylene is produced by reacting ethylene or ethylene with a small amount of comonomer in the presence of a peroxide by a high pressure radical polymerization process.

The linear low-density polyethylene is present in the presence of a catalyst containing so-called divalent metal compound (so-called TIGRA method), a molybdenum oxide catalyst (standard adsorbate method) supported on alimah, or silica-yramid. , Liquid or gas phase.

These low-density polyethylenes are not preferred because their density is less than 0.930 g / cm 3, and when they are 0.930 g / cm 3 or more, the transparency becomes poor.

An ethylene-vinyl acetate copolymer having a vinyl acetate content of 20% by weight or less is produced by reacting ethylene and vinyl acetate in the presence of a peroxide by a high pressure radical polymerization process. If the vinyl acetate content is more than 20% by weight, it is not preferable because the slag resistance and heat resistance deteriorate. It is preferable that the vinyl acetate content is in the range of 10 to 20% by weight in order to gradually bleed out the dropping agent (rubbing agent) at an appropriate amount and to sustain the long-term oil-repelling effect.

MFR of these polymers is 0.5-10, Preferably it is 0.5-5. If the MFR is too small, it is not preferable because the moldability of the film, in particular, the extrusion processability and the high-speed stretchability are deteriorated. In addition, an increase in MFR is undesirable because it causes an instability of the bubble in inspray forming to the forming properties of the film.

One type of these polymers may be selected and used for the surface layer, but two or more types of polymers may be blended and used. Moreover, it is also possible to add various polyolefin resins, rubber | gum, etc. in the range which does not impair the function as an inner layer.

The insecticide added to this inner layer can use the various insecticides well known in the art.

For example, nonionic, anionic, and cationic surfactants are used. Examples of these compounds include polyoxyalkylene ethers, partial esters of polyhydric alcohols, partial esters of alkylene oxide adducts of polyhydric alcohols, higher alcohol sulfate esters, alkali metal salts, alkylarylsulfonates, quaternary ammonium salts and fatty acid amine derivatives. Can be.

Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol monopalmitate, polyethylene glycol mono stearate, polyoxyethylene sorbitan mono laurate, polyoxyethylene sorbitan Monopalmitate, glycerin monolaurate, glycerin monopalmitate, glycerin monostearate, glycerin monoorate, pentaerythritol monolaurate, sorbitan monopalmitate, sorbitan mono behenate, sorbitan distearate , Diglycerin monoorate, triglycerine diorate, sodium laurylsulfate, sodium dedecyl benzenesulfonate, sodium butylnaphthalenesulfonate, cetyltrimethyl ammonium chloride, alkyldimethyl benzene diammonium chloride, dedecyl amine hydrochloride, lauric acid Urylamide ethylphosphate Salts, triethylcetyl ammonium iodide, orylamino diethylamine hydrochloride, basic pilidinium salts of dedecyl pilinidinium sulfate, and the like.

Among them, esters of polyhydric alcohols such as fatty acids having 14 to 22 carbon atoms with sorbitan, sorbitol, glycerin, polyglycerol, and polypropylene glycol, or nonionic surfactants mainly containing alkylene oxide adducts thereof may be mentioned.

It is also possible to select and use one kind of these insecticides, but two or more species of insecticides may be blended and used in order to simultaneously satisfy initial ruins, oil-resistance persistence, low-temperature ruins and the like.

Content of the weatherproofing agent is suitably selected in 0.1-2 weight% with respect to the polymer which comprises (A) layer. If it is less than 0.1 weight%, it is unpreferable because a falling-off property falls. When it exceeds 2 weight%, since heat resistance falls and the whitening of a film becomes remarkable at the time of use, such as the spring whose temperature rose, it is unpreferable.

(A) layer needs to satisfy 30 micrometers or more. If the thickness is smaller than this thickness, bad breathability becomes worse.

Although hydrotalcite which may be explained in detail in (B) layer may be added to this (A) layer, it is preferable that the addition amount is 3 or less with respect to a pesticide in a weight ratio. If it becomes more than this, the fall of the insect repellent property is remarkably unsuitable for use as an agricultural chemical film.

The ethylene-based resin constituting the layer (B) in the present invention is a high-pressure method low density polyethylene (branched low density polyethylene) having a density of less than 0.930, an ethylene-super-vinyl copolymer ethylene-alkyl (meth) acrylate copolymer, and an ethylene- α-olefin copolymers and the like. Of course, these resin can also be used individually or in mixture of 2 or more types.

High pressure low density polyethylene, ethylene, -vinyl acetate copolymer, ethylene-alkyl (meth) acrylate copolymer and the like having a density of less than 0.930 are produced by a high pressure radical process, and the MFR thereof is 0.5-10, preferably 0.5-5. Is used. If the MFR is too small, it is not preferable because the moldability of the film, in particular, the extrusion processability and the high-speed stretchability are deteriorated. In addition, an increase in MFR is not preferable because it causes moldability of the film, in particular, bubble instability in infraction molding. Among the polymers produced by the high pressure radical polymerization process, vinyl acetate content of 45% by weight or less, particularly 20% by weight or less of ethylene-vinyl acetate copolymer is most preferred in view of transparency, heat retention, heat fusion resistance, and price.

The ethylene-α-olefin copolymer is a copolymer of ethylene and α-olefins such as flopylene, butene-1, hexene-1,4-methylpentene-1 and octene, and the copolymer contains a transition metal compound Copolymerization is carried out in the liquid phase or in the gas phase in the presence of a catalyst (so-called thiigla method), a chromium oxide catalyst (Phillips method) supported on alumina or silica-alumina, and a molybdenum oxide catalyst (standard method) supported on alumina. It is prepared and the melt fluate (hereinafter abbreviated as MFR. Unit g / 10min) is 0.5 to 20, preferably 0.5 to 10, and density is 0.940 g / cm 3 or less, preferably 0.935 / cm 3 or less. Linear low density polyethylene is suitable.

If the MFR is too low, it is not preferable because the moldability of the film, in particular, the extrusion processability and the high-speed stretchability are deteriorated. In addition, when the MFR increases, the mechanical strength decreases, which is not preferable. Too high a density is undesirable since transparency is lost. If the density is too low, it is not preferable because the waist is weakened and the overall workability is insufficient.

Hydrotalcite or its flexible compound added to layer (B) (hereinafter abbreviated as hydrotalcite)

Wherein M ²⁺ represents a divalent metal ion selected from the group consisting of Mg, Ca and Zn, A ^n- represents an n-valent anion, and x and m satisfy the conditions

It is a compound represented by these, its baking etc.

등과 같은 음이온을 예시할 수 있다.As an example of the n-valent anion represented by A ^n- in said Formula (1),

And anions such as these.

), 알카마이자-2(x=0.33, m=0, A=

)등을 들 수 있다.Specific examples thereof include Alkamyza-1 (x = 0.33, m = 0, A =

), Alkamyza-2 (x = 0.33, m = 0, A =

), And the like.

And 10 micrometers or less are preferable for the average particle diameter, Especially 3 micrometers or less are used more suitably. When the average particle diameter exceeds 10 mu, the strength and transparency of the film are greatly reduced, making it difficult to use as an agricultural film. Moreover, in order to improve the dispersibility of the said hydrotalcite, an example of a surface treatment agent is a paraffin, a fatty acid, a higher alcohol, a polyhydric alcohol, a chitanate-type capping agent, a silane-type capping agent, etc. are mentioned.

The amount of hydrotalcite to be used is appropriately selected from echelen resin / hydrotalcites = 99 to 60/1 to 40 parts by weight. More preferably, the ratio is 98-75 / 2-25.

If the amount is out of the above-mentioned range, too small, the so-called infrared absorbing ability will be lowered, and the ability to prevent night infrared rays from penetrating and emitting the agricultural film will be insufficient. In other words, the insulation is insufficient.

On the other hand, if the amount is out of range and becomes too large, dispersion of resin and hydrotalcite becomes insufficient, transparency greatly decreases, and visible light transmittance decreases. For this reason, the permeation | transmission of the agricultural film of solar energy in the daytime decreases, so that the temperature in the house does not rise, and eventually, the amount of the ether needed for the growth of the crop is lowered, resulting in poor growth. In addition to the decrease in transparency, the mechanical strength of the film is further lowered and the film is easily torn, resulting in poor electrical workability.

The second layer can contain a dropping agent. This antiseptic agent prevents the antiseptic agent of the inner layer (A) layer from moving to the outer layer during the film length, and consequently prevents the inner layer of the antiseptic concentration from thinning or the antiseptic agent of the inner layer surface flows down by the water droplets, and the antiseptic performance is short. In the case of lowering the role of spreading the repellent. Therefore, the concentration is not particularly defined, but it is preferable to contain 0.1 to 2% by weight as the inner layer. Moreover, the rainproofing agent to be used may be the same as the said inner layer, and may differ from an inner layer, for example, may use slow-release rainproofing agent.

However, it is preferable that the (B) layer does not contain the antiseptic agent in the diesel oil used in the (B) layer present in the outer layer and to be applied to the outside of the house, but the ratio of the piglet / hydrotalside is 0.3 or less, preferably If it is 0.1 or less, you may add. If it exceeds this, the film | membrane will bleed out on the outer surface of a film, the film contamination resulting from whitening of a film, the dust, sand adhered to the outdoors, will generate | occur | produce, and finally the visible light transmittance of a film will fall, It is not desirable because its agricultural permeation is reduced.

The film of the present invention

(1) Inner layer (A) / outer layer (B)

(2) Inner layer (A) / middle layer (B) / outer layer (C)

(3) Inner layer (A) / middle layer (C) / outer layer (B)

(4) Inner layer (A) / middle layer (B) / middle layer (D) / outer layer (C)

(5) Inner layer (A) / middle layer (D) / middle layer (B) / outer layer (C)

(6) inner layer (A) / middle layer (D) / middle layer (B) / middle layer (D) / outer layer (C)

(7) Inner layer (A) / middle layer (D) / middle layer (B) / middle layer (E) / outer layer (C)

Etc. It can be used as various multilayer films of two or more layers.

As resin used for each layer other than (A) layer and (B) layer, the ethylene resin demonstrated about layer (B), ie, low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-alkyl (meth) acrylate copolymer, and ethylene- (alpha)-olefin copolymer etc. can be used. To these layers, hydrotalcite and loss controlling agent can be added as needed. The concentration of hydrotalside is 60% or less for the reasons described above. The insect repellent can select suitably the various insect repellents demonstrated by the inner layer (A).

The outer surface layer is preferably composed of linear low density polyethylene in terms of transparency, mechanical strength, scratch resistance, and electrical workability. However, when too many hydrotalcites are put in this resin, the folded gold of a film will become white easily. In order to prevent this, a layer of one-layer ethylene-vinyl acetate copolymer is also provided, and this layer is also made to contain hydrotalcites.

That is, the multilayer film most suitable for the objective of this invention is an inner surface layer which consists of a vinyl acetate content 10-20 weight% ethylene-vinyl acetate copolymer containing 0.1-2 weight% of droppers, 1-40 weight In an outer surface layer composed of linear low density polyethylene containing% hydrotalcite or a flexible compound thereof, and an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20% by weight or less containing 1 to 40% by weight of hydrotalcite. It has an intermediate layer.

The barley of the multilayer film of this invention may be added to each layer, and may be used.

Each layer having the above structure may contain various other additives commonly used in the art as required.

Examples of such other additives include antioxidants, light stabilizers, ultraviolet absorbers, antistatic agents, lubricants, anti-locking agents, anti-fogging agents, and the like, and various additives well known in the art.

The agricultural film of this invention is shape | molded not only a colorless film but also the film colored with pigment, dye, etc ..

The film of the present invention is molded by an inflation method, a cast method or the like, and the total thickness thereof is in the range of 0.035-0.3 mm, preferably in the range of 0.05-0.2 mm, in consideration of strength, performance, production cost, and the like. Moreover, as for the ratio of the thickness of each layer, the thickness ratio of each layer can be arbitrarily selected as long as the sum total of the thickness of (A) layer and (B) layer satisfy | fills 0.03 mm or more.

The agricultural multilayer film of this invention is useful as a constituent film material for facility cultivation, such as a greenhouse, a tunnel, and curtains.

The inventors of the present invention have investigated a method for producing an agricultural thermal insulation coating film superior to a soft polyvinyl chloride film using an ethylene polymer.

(1) Infrared absorber used in the present invention is hydrotalcite is one of the most excellent as an additive in the heat-insulating agricultural film, excellent in the infrared absorption effect, the thermal insulation effect is formed with the increase in the amount of addition, appearance, transparency In this regard, the limit is preferably 40%, preferably 25%.

(2) In order to prevent the light transmittance from being lowered due to condensation on the inner surface of the film, use of a dropping agent is necessary.

(3) However, since hydrotalcite adsorbs a mole-proofing agent (oil agent), it is necessary to mix | blend hydrotalcite in the layer different from the layer which makes a film multilayer and contains a mole-proofing agent.

(4) In view of the performance of the flocculants and the persistence of the effect, the flocculant compounding resin layer should be low density polyethylene or ethylene-vinyl acetate copolymer, preferably 10-20% by weight of vinyl acetate.

(5) As the hydrotalcite compounding resin layer, it is preferable to use an appropriately selected among ethylene resins in consideration of strength, scratch resistance, electric field workability and filler holding ability.

The agricultural multilayer film of the present invention is excellent in heat retention, heat fusion resistance, transparency, dustproofing, and work strength and is superior to polyvinyl chloride film in terms of stain resistance and disposal. Therefore, it is extremely useful as a coating film for plant cultivation.

EXAMPLE

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail according to an Example, and this invention is not limited to the following examples, unless the summary is exceeded.

[Example 1-3, Comparative Example 1-7]

Using a 150mm ψ (manufactured by Tommy Machinery Co., Ltd.) on a three-layer die as a three-layer inflation molding apparatus, the extruder is a 40 mm squeezer extruder (manufactured by Modern Mashinari Co., Ltd.) and a 45 mm squeeze extruder (Praco Co., Ltd.) The multilayered or single-layer film of the structure shown in the 1st table was obtained by making the inner layer into the 50 mm (psi) extruder (made by Modern Masinari Co., Ltd.) at the shaping | molding temperature of 160 degreeC, blow ratio 1.5, and taking-out speed of 5 m / min. Moreover, the commercial item was used for the soft polyvinyl chloride film.

Each film was subjected to the following evaluation test. The results are shown in the first table.

(1) low temperature loss agent

The upper portion of the thermal container (15 cm in diameter and 17 cm in height) containing water at 25 ° C. up to two-thirds of the container's capacity is sealed and placed in a cold air circulation cold room at −10 ° C., and returned to room temperature after 20 hours. It was time to stand still. This cycle was repeated seven times.

The 10 steps were evaluated by setting the case where the film was completely cloudy due to condensation water droplets as 10 when completely cloudy and no clouding occurred at all.

(2) persistence

The sample film was loaded with a 5 ° inclination on a horizontal plane in a constant temperature water bath maintained at 50 ° C, and the condensation of water on the inner surface of the film was observed over time, and evaluated in ten steps, such as the low-temperature half-pound. .

(3) dustproof

Four laminated films were lengthened in the tunnel prepared for the measurement of heat retention described below, and the result was determined as a reduction rate for transparency (solar transmittance) at the beginning of the full length of transparency (solar transmittance) after 4 months. Solar light transmittance was measured with the illuminometer (ANA 300 type by Tokyo Photoelectric Co., Ltd.).

A-3% or less, B-3-10%, C-10% or more

(4) warmth

The laminated film was transferred to an arch-shaped temporary body in a sealed state to form a tunnel. The arch-shaped hypothesis was about 0.65m in height and 1.5m in width.

The temperature difference between the 20 cm high house and the outside of the house was measured every 10 minutes (from Chibiquichi Ichihara City, January 1986) and the average of 7 days from 6 pm to 6 am the next morning was calculated. The results are shown in Table 1.

(5) Breaking point strength

By the tensile test (based on JIS K 6783), the breaking point strength of the laminated film in the MD direction and the TD direction was measured.

(6) breaking elongation

The elongation at break in the MD direction and the TD direction of the laminated film was measured as in the method of measuring the breaking point strength.

(7) Falling Impact Strength

It measured according to ASTM D 1709 A method.

(8) film steepness

Film steepness was measured by Hnadle-O-Meter.

(9) tensile strength

In accordance with JIS K 6783, the tensile strength in the MD direction and the TD direction of the laminated film was measured.

Each result is shown in Table 1.

TABLE 1

Example 4-9 and Comparative Example 7A-16

Using a 150mm ψ (manufactured by Tommy Machinery Co., Ltd.) on a three-layer die as a three-layer inflation shaping machine, the extruder has an outer layer of 40 mm ψ (made by Modern Machinery Co., Ltd.) and an intermediate layer of 45 mm ψ extruder (manufactured by Flaco Corporation). ) The inner layer was made into a 50 mm ψ extruder (manufactured by Modern Marine Co., Ltd.) to obtain a multilayer or single-layer film having the configuration shown in the second table at a molding temperature of 160 ° C., a blow ratio of 1.5 and a pulling rate of 5 m / min. In addition, a commercial item was used for the soft polyvinyl chloride film.

Each film was evaluated for evaluation as in Example 1. The results are shown in the second table.

TABLE 2

Example 10-13, Comparative Example 17-20

150 mm ψ (manufactured by Tommy Machinery Co., Ltd.) is used for the three-layer die as a three-layer inflation molding apparatus, and the extruder is a 40 mm φ extruder (manufactured by Modern Machinery Co., Ltd.) and an intermediate layer is 45 mm ψ (Placo Corporation). The multilayer or single-layer film of the structure shown in the 3rd table | surface was obtained by making the inner layer into the 50 mm (psi) extruder (made by Modern Marine Co., Ltd.) at the shaping | molding temperature of 160 degreeC, blow ratio 1.5, and a pulling speed of 5 m / min. In addition, a commercial item was used for the soft polyvinyl chloride film.

Each film was evaluated for evaluation as in Example 1. The results are shown in the third table.

TABLE 3

Example 14-17

[Comparative Example 21-24]

A 150 mm ψ (made by Tommy Machinery Co., Ltd.) is used for the three-layer die as a three-layer inflation molding apparatus, and the extruder is a 40 mm φ extruder (manufactured by Modern Machinery Co., Ltd.) and the middle layer is a 45 mm φ extruder (manufactured by Fraco Co., Ltd.). ) And the inner layer were obtained by using a 50 mm psi extruder (manufactured by Modern Machinery Co., Ltd.) at a molding temperature of 160 ° C., a brobby 1.5, and a take-out speed of 5 m / min. In addition, a commercial item was used for the soft polyvinyl chloride film.

Each film was evaluated for evaluation as in Example 1.

The results are shown in the fourth table.

In addition, fusion temperature was performed as follows. The inner surfaces of the film are overlapped with each other to irradiate infrared rays. The thermocouple is set on the opposite side to the infrared irradiation surface of the film, and the temperature is measured. The adhesive strength between inner surfaces of the film after irradiation is measured. The melting temperature is set to a temperature corresponding to 20g / 20mm width. The measurement conditions of adhesive strength were performed at 23 degreeC and the crosshead speed | rate 300mm / min.

TABLE 4

Claims (7)

Consists of two or three or more multilayer films, and one surface layer (A) is composed of low density polyethylene containing 0.1 to 2% by weight of rain repellent or ethylene-vinyl acetate copolymer having a vinyl acetate content of 20% by weight or less An agricultural film, characterized in that the layer is composed of an ethylene resin containing 1 to 40% by weight of hydrotalcite or a related compound thereof, at least another layer (B). The multilayer film of Claim 1 whose content is 3 or less with respect to a pesticide in weight ratio, even if one surface layer (A) does not contain hydrotalcite or its related compound. The multilayer film according to claim 1, wherein at least the other one layer (B) contains or does not contain a dust repellent, and the content thereof is 0.3 or less with respect to hydrotalcite or its related compound by weight ratio. The multilayer film of Claim 1 whose ethylene resin in at least another 1 layer (B) is low density polyethylene, the vinyl acetate content 20 weight% or less of ethylene-vinyl acetate copolymer or ethylene-alpha-olefin copolymer resin. The multilayer film of claim 1, wherein the ethylene-αolefin copolymer resin is a linear low density polyethylene. The multilayer film according to claim 1, wherein one surface layer (A) is an inner surface layer of the multilayer film. The inner surface layer which consists of vinyl acetate content of 10-20 weight% of vinyl acetate content containing 0.1 to 2 weight% of droppers, linear form containing 1 to 40 weight% of hydrotalcite or its flexible compound An agricultural multilayer film comprising an outer surface layer composed of a low density polyethylene and an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20% by weight or less and containing 1 to 40% by weight of hydrotalcite.