JP2018123174A - Resin composition and molded body of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition capable of obtaining a molded body excellent in surface smoothness, appearance and releasability even when containing fatty acid ester, and to provide a molded body excellent in surface smoothness, appearance and releasability.SOLUTION: A resin composition contains a thermoplastic resin, silylated polyolefin and fatty acid ester having a molecular weight of 100-10,000. A molded body is molded from the resin composition.SELECTED DRAWING: None

Description

    The present invention relates to a resin composition and a molded body thereof.

Thermoplastic resins are used in various situations because they are inexpensive and easy to mold. However, when a thermoplastic resin is molded and used as a packaging material, the contents adhere to the packaging material and are difficult to remove, or the contents adhered to the packaging material after removal are discarded together with the packaging material and the yield There are problems such as lowering. Fatty acid esters such as glycerin fatty acid esters and sorbitan fatty acid esters are used for the purpose of imparting releasability to the packaging material and reducing adhesion of contents. Since these fatty acid esters are highly safe and relatively inexpensive, they are suitably used for general purposes such as food packaging materials.
Patent Documents 1 and 2 describe that a surfactant is blended in a sealant layer in contact with a viscous material, or that a film is formed by applying a surfactant in advance to the inner surface of a packaging material.

JP 2000-355362 A JP 2001-48229 A

However, as a result of investigations by the present inventors, it has been found that when a fatty acid ester is added to a thermoplastic resin, the dispersibility of the fatty acid ester in the resin is poor and a non-uniform resin composition tends to be formed. Therefore, in a molded article such as a film prepared using the obtained resin composition, the fatty acid ester is likely to be precipitated on the surface of the molded article, the smoothness of the molded article surface is lowered, or the appearance of the molded article is deteriorated. It turns out that there is a problem. Moreover, since fatty acid ester is easy to bleed out from the surface of a molded object, there is a concern that the mold release effect tends to be lowered. Accordingly, an object of the present invention is to provide a resin composition capable of obtaining a molded article excellent in surface smoothness, appearance, and releasability even when a fatty acid ester is contained, and to provide surface smoothness, appearance, release properties. It is to provide a molded article having excellent moldability.

That is, according to the present invention, the following resin composition and molded article are provided.
[1] A resin composition comprising a thermoplastic resin, a silylated polyolefin, and a fatty acid ester having a molecular weight of 100 to 10,000.
[2] The resin composition according to [1], wherein the thermoplastic resin is polyolefin.
[3] A molded article molded from the resin composition according to [1] or [2].
[4] The molded article according to [3], wherein the molded article is a film or a sheet.
[5] The molded article according to [3] or [4], which is a container or a packaging material.

  According to the present invention, a resin composition capable of obtaining a molded article excellent in surface smoothness, appearance, and releasability even when containing a fatty acid ester, and excellent in surface smoothness, appearance, and releasability. A molded body can be provided.

    Hereinafter, embodiments of the present invention will be described. In addition, unless otherwise indicated, the symbol "ab" which shows the numerical range in a sentence shall express from a to b or less.

The resin composition of the present invention includes a thermoplastic resin, a silylated polyolefin, and a fatty acid ester having a molecular weight of 100 to 10,000.
(Thermoplastic resin)
Examples of the thermoplastic resin include polyolefin, polyvinyl chloride, polyvinylidene chloride, ethylene / vinyl acetate copolymer, ethylene / methacrylic acid copolymer, polyester such as polyethylene terephthalate, polycarbonate, polyamide, ABS resin, polyacetal resin, polyimide, Examples thereof include polyurethane and polylactic acid.
Of these, polyolefin is preferable. Here, the polyolefin refers to a polyolefin containing no silicone chain in the structural unit. Examples of the polyolefin include a polymer containing a structural unit derived from an olefin having 2 to 20 carbon atoms. Preferred polyolefins include ethylene homopolymers or copolymers and propylene homopolymers or copolymers.
The ethylene content in the ethylene homopolymer or copolymer is preferably 50 to 100 mol%, more preferably 60 to 100 mol%. Examples of the copolymer component include α-olefins having 3 or more carbon atoms.
The MFR (ASTM D1238, 190 ° C., 2.16 kg load) of ethylene homopolymer or copolymer is preferably, for example, 0.01 to 80 g / 10 min, and more preferably 0.1 to 50 g / 10 min.
Low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene and the like are also preferable polyethylene.
As propylene homo- or copolymer, the propylene content is preferably 50 to 100 mol%. Examples of the copolymer component include ethylene and α-olefins having 4 or more carbon atoms.

The MFR (ASTM D1238, 230 ° C., 2.16 kg load) is, for example, preferably 0.1 to 100 g / 10 minutes, and more preferably 0.3 to 50 g / 10 minutes.
(Silylated polyolefin)
The silylated polyolefin may have any structure as long as it has a silicone chain and a polyolefin chain. For example, silicone grafted polyolefin having a structure in which silicone is grafted on polyolefin, block copolymer of polyolefin and silicone, structure in which polyolefin is grafted on silicone, structure in which polyolefin is grafted on the silicone part of the block copolymer it can.
Examples of the block copolymer include a block copolymer bonded in the order of (polyolefin chain)-(silicone chain), and a block copolymer bonded in the order of (polyolefin chain)-(silicone chain)-(polyolefin chain). Can do.
Examples of the polyolefin chain include a polymer chain containing a structural unit derived from an olefin having 2 to 50 carbon atoms, preferably 2 to 20 carbon atoms.
Especially, what has a structure represented by following formula (1) is preferable.

(In the above formula (1), A ¹ , A ² and A ³ are each independently a polyolefin chain or a hydrocarbon group having 1 to 20 carbon atoms. R is a hydrocarbon group having 1 to 20 carbon atoms. Each R may be the same or different, m is an integer of 1 to 10,000, and when a plurality of A ³ are present, each A ³ may be the same or different, provided that A ¹ , A ² , A ³ represents at least one polyolefin chain.)
The polyolefin chain in A ¹ , A ² and A ³ is a polymer chain including a structural unit derived from an olefin having 2 to 50 carbon atoms, preferably 2 to 20 carbon atoms, for example.

  Specific examples of the olefin having 2 to 50 carbon atoms include ethylene and an α-olefin having 3 to 50 carbon atoms (propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4 -Methyl-1-pentene, 3-methyl-1-pentene, 3,4-dimethyl-1-pentene, 4-methyl-1-hexene, 3-ethyl-1-pentene, 3-ethyl-4-methyl-1 -Pentene, 3,4-dimethyl-1-hexene, 4-methyl-1-heptene, 3,4-dimethyl-1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene 1-octadecene, 1-eicocene, vinylcyclohexane, etc.).

Among these, ethylene and an α-olefin having 3 to 12 carbon atoms are preferable, ethylene and an α-olefin having 3 to 8 carbon atoms are more preferable, and ethylene is particularly preferable.
The polyolefin chain may be a homopolymer chain or a copolymer chain.

Especially, the polymer chain comprised only from C2-C50 olefin chosen from ethylene and C3-C50 alpha olefin is preferable, Furthermore, ethylene homopolymer chain, propylene homopolymer chain, Alternatively, an ethylene / C3-C20 α-olefin copolymer chain is preferred. In the copolymer chain of ethylene / C3-C20 α-olefin, when all the structural units are 100 mol%, the structural unit derived from C3-C20 α-olefin exceeds, for example, 0 mol%. It can also be 20 mol% or less, and can also be over 0 mol% and 10 mol% or less.
Moreover, the said polyolefin chain may also contain the structural unit derived from another olefin as needed. Other olefins include olefins containing an internal double bond such as cis-2-butene; vinylidene compounds such as isobutene; aryl vinyl compounds such as styrene; arylvinylidene compounds such as α-methylstyrene; and functionalities such as methyl methacrylate. Group-substituted vinylidene compounds; aliphatic cyclic olefins containing internal double bonds such as 5-methyl-2-norbornene, tetracyclododecene, cyclopentadiene, dicyclopentadiene; cyclic olefins containing an aromatic ring such as indene; butadiene, Examples thereof include linear or cyclic polyenes such as isoprene, ethylidene norbornene and vinyl norbornene.
The content of structural units derived from other olefins is preferably 0 to 10 mol%, more preferably 0 to 5 mol%, assuming that all the structural units constituting the polyolefin chain are 100 mol%.
The polyolefin chain preferably has a number average molecular weight of 100 or more and 500,000 or less, more preferably 200 or more and 100,000 or less, further preferably 500 or more and 50,000 or less, and more preferably 700 or more. 10,000 or less is more preferable.
The polyolefin chain preferably has a molecular weight distribution (Mw / Mn) determined by the following GPC method in the range of 1.1 to 3.0.

GPC measurement method:
GPC measurement can be performed at a temperature of 140 ° C. using orthodichlorobenzene as a solvent, and analytical values (weight average molecular weight (Mw), number average molecular weight (Mn) and Mw / Mn) can be obtained as polyethylene conversion values. .
The measurement can be performed under the following conditions. The molecular weight can be determined based on the following conversion method by creating a calibration curve using commercially available monodisperse standard polystyrene.
Apparatus: Gel permeation chromatograph Alliance GPC2000 (manufactured by Waters)
Solvent: o-dichlorobenzene column: TSKgel column (manufactured by Tosoh Corporation) x 4
Flow rate: 1.0 ml / min Sample: 0.15 mg / mLo-dichlorobenzene solution temperature: 140 ° C.
Molecular weight conversion: PS conversion / general-purpose calibration method The coefficient of the Mark-Houwink viscosity equation shown below can be used for calculation of general-purpose calibration.
Coefficient of polystyrene (PS): KPS = 1.38 × 10 ⁻⁴ , aPS = 0.70
Coefficient of polyethylene (PE): KPE = 0.06 × 10 ⁻⁴ , aPE = 0.70

In the above A ¹ , A ² , A ³ and R, examples of the hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms include an alkyl group, an arylalkyl group, an alkenyl group and an aryl group. .

Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, hexyl group, 2-ethylhexyl group, octyl group, decyl group, and octadecyl group. A linear or branched alkyl group; a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group and a norbornyl group;
Examples of the arylalkyl group include a benzyl group, a phenylethyl group, and a phenylpropyl group.
Examples of the alkenyl group include a vinyl group, a propenyl group, and a cyclohexenyl group.
Examples of the aryl group include a phenyl group, a tolyl group, a dimethylphenyl group, a trimethylphenyl group, an ethylphenyl group, a propylphenyl group, and a naphthyl group.

  In the above formula (1), m is an integer of 1 to 10,000. m is preferably 5 or more, and more preferably 10 or more. Further, m is preferably 1,000 or less, more preferably 300 or less, and even more preferably 50 or less.

All of A ¹ , A ² , and ^one or plural A ³ may be polyolefin chains, or some groups may be polyolefin chains and others may be hydrocarbon groups having 1 to 20 carbon atoms. .

In the above formula (1), m is equal to or greater than 2, when at least one of A ³ that is different from the other A ^3, but plural kinds of the following units are present, not particularly limited in its aligned sequence, block Or random.

As said formula (1), the structure represented by following (1A), (1B) or (1C) is preferable, and (1A) is more preferable among these.
(1A) In the above formula (1), A ¹ and A ² are polyolefin chains, and A ³ is a hydrocarbon group having 1 to 20 carbon atoms.
(1B) In the above formula (1), one of A ¹ and A ² is a polyolefin chain, the other is a hydrocarbon group having 1 to 20 carbon atoms, and A ³ is a hydrocarbon group having 1 to 20 carbon atoms. There is a structure.
(1C) In the above formula (1), A ¹ and A ² are hydrocarbon groups having 1 to 20 carbon atoms, and at least one of A ³ is a polyolefin chain.

  In the silylated polyolefin according to the present invention, the silicone chain / polyolefin chain (weight ratio) is not particularly limited, but is preferably 5/95 to 99/1, and more preferably 10/90 to 95, for example. / 5.

  Although the manufacturing method of the silylated polyolefin based on this invention is not specifically limited, For example, it can manufacture by the method described in paragraphs 0089-0145, paragraphs 0196-0207, etc. of WO2012 / 098865 gazette.

(Fatty acid ester)
Examples of the fatty acid ester include esters that are a reaction product of a fatty acid and an alcohol.
The fatty acid is preferably a saturated or unsaturated, linear or branched fatty acid having 6 to 22 carbon atoms. Specifically, for example, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, nonadecanoic acid, Arachidic acid, gadoleic acid, eicosadienoic acid, arachidonic acid, behenic acid, erucic acid, docosadienoic acid, lignoceric acid, isostearic acid, ricinoleic acid, 12-hydroxystearic acid, 9-hydroxystearic acid, 10-hydroxystearic acid, hydrogenated Castor oil fatty acid (fatty acid containing a small amount of stearic acid and palmitic acid in addition to 12-hydroxystearic acid) and the like. Among these, caprylic acid, capric acid, and stearic acid are preferable.
On the other hand, as alcohols, monovalent alcohols such as methanol, ethanol, propanol, isopropanol, butanol, tert-butanol, hexanol, octanol; ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, polyalkylene glycol, sorbitol And polyhydric alcohols such as sucrose, glycerin and polyglycerin. As the alcohol, polyhydric alcohol is preferable, and polyglycerin is more preferable.

  The molecular weight of the fatty acid ester used in the present invention is from 100 to 10,000, preferably from 200 to 5,000, and more preferably from 400 to 2,000.

(Resin composition)
In the resin composition, the content ratio (mass ratio) of the thermoplastic resin (A), the silylated polyolefin (B), and the fatty acid ester (C) having a molecular weight of 100 to 10,000 is (A) / (B) / (C). = 60 to 99.45 / 0.5 to 30 / 0.05 to 10, more preferably 72 to 98.9 / 1.0 to 20 / 0.1 to 8.0, More preferably, it is 85-97.5 / 2.0-10 / 0.5-5.0.

The resin composition may be composed only of a thermoplastic resin, a silylated polyolefin, and a fatty acid ester having a molecular weight of 100 to 10000, but if desired, other resins and additives may be added as long as the object of the present invention is not impaired. Etc. can be included. Examples of additives include plasticizers, UV stabilizers, anti-coloring agents, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, yarn friction reducing agents, slip agents, mold release agents, An oxidizing agent, an ion exchange agent, a coloring pigment, and the like can be added.
Moreover, other oils can be added as needed. Examples of other oils include edible oil and silicone oil. These oils are added in an amount of preferably 0.05 to 10% by mass, preferably 0.1 to 5% by mass with respect to the entire resin composition.

Each component can be melt-kneaded using a known method, for example, a single-screw or twin-screw extruder, a kneader, a Henschel mixer, a Banbury mixer, a tumbler mixer, etc., and may be used after being pelletized as necessary. it can.
Further, a master batch having a high concentration of silylated polyolefin may be prepared, and the master batch may be diluted with polyolefin and used.

(Molded body)
The shaped product of the present invention may have any shape, but is preferably a film or a sheet.
The molded body of the present invention is obtained by molding the resin composition by a known method such as an extrusion molding method, an injection molding method, a melt casting method, an inflation molding method, a compression molding method, a transfer molding method, or a casting molding method. Can do.
Moreover, the molded body of the present invention may be a laminated body in which a layer made of the resin composition and another layer are laminated by a known method such as coextrusion molding or bonding. The resin composition layer and other layers may each be one layer or two or more layers. Further, the materials constituting the other layers can be appropriately selected from various materials such as resin, metal, paper, and cloth depending on the application.

(Use)
Examples of uses of the molded article of the present invention include, but are not limited to, the following.
Water repellent film; oil repellent film; container, packaging material (for food, etc.); surface protective film;

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.
In the following examples and comparative examples, various analysis methods were performed according to the following procedures.

<Surface free energy>
Static contact with water, diiodomethane, and bromonaphthalene using the solid-liquid interface analysis system (DropMaster500 image processing type, manufactured by Kyowa Interface Science Co., Ltd.) on the surface of the press sheet under the conditions of 23 ° C. and 50% RH The corner was measured. For each liquid sample, measure 5 times each and use the average value as the contact angle of the sample, and calculate the surface free energy (mN / m) of the sheet from the Fowkes diffusion formula using the surface tension component value of each liquid sample. did.

<Arithmetic surface roughness Ra>
About the surface of the press sheet, arithmetic mean roughness Ra (micrometer) was measured 5 times using the surface roughness measuring machine (Surfcom 130A, Tokyo Seimitsu make), and the average value was computed.

<Appearance>
The press sheet was visually observed and the appearance was evaluated according to the following evaluation criteria. Here, it was defined as a feeling of glittering together with appearance defects such as non-uniformity of transparency within the sheet surface and flow unevenness, which may be caused by poor dispersion of the additive.
―Appearance evaluation criteria―
○: No glare (uniform appearance in the sheet surface)
×: Glittering

<Separation>
The press sheet was cut into a 110 mm × 100 mm rectangle to produce a cylindrical sample with a diameter of 35 mm and a height of 100 mm. After 25 g of mayonnaise was spread on the inner surface of the obtained cylindrical sample, the cylindrical sample was erected, and the appearance of the mayonnaise falling on the inner surface was observed for 60 minutes.
The change in the height of the uppermost part of the part where the mayonnaise adheres to the inner surface after about 60 minutes is regarded as the amount of fall of the mayonnaise, and the evaluation of the separability according to the following evaluation criteria with respect to the × evaluation of Comparative Example 1 As a result.
―Evaluation criteria for personality―
A: Very good (the amount of mayonnaise falling is 300% or more of Comparative Example 1)
○: Good (the amount of mayonnaise falling is 150% or more and less than 300% of Comparative Example 1)
X: Defect (the amount of mayonnaise falling is less than 150% of Comparative Example 1)

[Synthesis Example 1]
One-end vinyl group-containing ethylene polymer (P-1) was synthesized by the method described in Synthesis Example 2 of International Publication No. 2012/098865. The physical properties of this one-end vinyl group-containing ethylene polymer (P-1) (single unit) were as follows.
Melting point (Tm) 127 ° C
Mw = 4800, Mn = 2087, Mw / Mn = 2.3 (GPC)
Terminal unsaturation 97%

[Synthesis Example 2]
A 300 ml two-necked flask was charged with 25.1 g (11.8 mmol) of the one-end vinyl group-containing ethylene polymer (P-1) obtained in [Synthesis Example 1], and hydrosilane A ( 6.2 g (5.9 mmol; equivalent to 11.8 mmol as Si-H group) of Gelest, Inc., DMS-H112) and a platinum catalyst composition prepared according to Synthesis Example 3 of International Publication No. 2012/098865 (C 150 μl (1.4 × 10 ⁻⁶ mmol in terms of Pt) of -1) diluted 200-fold with hydrosilane A was charged. The reactor was set in an oil bath that had been heated to an internal temperature of 130 ° C. in advance, and stirred. The mixture was stirred in an oil bath for 6 hours and then cooled, about 200 ml of methanol was added, and the contents were taken out into a 300 ml beaker and stirred for 2 hours. Thereafter, the solid is collected by filtration and dried, whereby in formula (1), A ¹ and A ² are ethylene homopolymer chains, A ³ is a methyl group, R is a methyl group, and m is 12 33.5 g of white solid silylated polyolefin (B-1) which was ˜13 was obtained. As a result of NMR analysis, the obtained silylated polyolefin (B-1) had a yield of 99%, an olefin conversion rate of 100%, and an isomerization rate of 1%. The number average molecular weight analyzed by GPC was 5,000.
Hydrosilane _{A: HSi (CH 3) 2} O - (- Si (CH 3) 2 -O-) n -Si (CH 3) 2 H
(N = 12-13)

[Example 1]
89 parts by weight of polypropylene (polypropylene manufactured by Prime Polymer Co., Ltd., F300SP), 10 parts by weight of silylated polyolefin (B-1) obtained in Synthesis Example 2, Panaceto 810 (manufactured by NOF Corporation, tri (capryl / capric acid) glyceryl) ) 1 part by weight was melt kneaded at a temperature of 200 ° C. for 5 minutes using a lab plast mill (manufactured by Toyo Seiki Seisakusho Co., Ltd.) to obtain a resin composition. Then, using a hydraulic heat press machine manufactured by Shin-Fuji Metal Industry Co., Ltd., pressurizing the resin composition at a temperature of 200 ° C. for 5 minutes, and then setting it at a temperature of 20 ° C., another hydraulic heat press manufactured by Shin-Fuji Metal Industry Co., Ltd. Using a press, the pressure was applied for 3 minutes to obtain a press sheet having a thickness of 200 μm. Table 1 shows the measurement results of various physical properties of the obtained press sheet.

[Example 2]
The resin composition was composed of 85 parts by weight of polypropylene (polypropylene manufactured by Prime Polymer, F300SP), 10 parts by weight of silylated polyolefin (B-1) obtained in Synthesis Example 2, and panacet 810 (manufactured by NOF Corporation, Tri (Capryl / capric acid) glyceryl) The same operation as in Example 1 was performed except that the amount was changed to 5 parts by weight.
The results are shown in Table 1.

[Example 3]
The same operation as in Example 1 was performed except that Sunsoft Q-18S (manufactured by Taiyo Kagaku Co., Ltd., decaglycerin monostearate) was used instead of panacet 810.
The results are shown in Table 1.

[Example 4]
The same operation as in Example 1 was performed except for Sunsoft Q-1810S (manufactured by Taiyo Kagaku Co., Ltd., decastearate decaglycerin) instead of panacet 810.
The results are shown in Table 1.

[Comparative Example 1]
Another Kamito Metal Industry Co., Ltd., which was set at a temperature of 20 ° C. after pressurizing polypropylene (polypropylene manufactured by Prime Polymer Co., Ltd., F300SP) at a temperature of 200 ° C. for 5 minutes using a hydraulic hot press machine manufactured by Kamito Metal Industry Co., Ltd. Pressing was performed for 3 minutes using a hydraulic hot press machine manufactured to obtain a press sheet having a thickness of 200 μm. Table 1 shows the measurement results of various physical properties of the obtained press sheet.

[Comparative Example 2]
Without using silylated polyolefin (B-1), the composition of the resin composition was 99 parts by weight of polypropylene (polypropylene manufactured by Prime Polymer Co., Ltd., F300SP), panacet 810 (manufactured by NOF Corporation, tri (capryl / capric acid) glyceryl). ) The same operation as in Example 1 was performed except that the amount was changed to 1 part by weight.
The results are shown in Table 1.

[Comparative Example 3]
The same operation as in Comparative Example 2 was performed except that Sunsoft Q-18S (manufactured by Taiyo Kagaku Co., Ltd., decaglycerin monostearate) was used instead of Panacet 810.
The results are shown in Table 1.

[Comparative Example 4]
The same operation as in Comparative Example 2 was performed except for Sunsoft Q-1810S (manufactured by Taiyo Kagaku Co., Ltd., decastearate decaglycerin) instead of panacet 810.
The results are shown in Table 1.

As shown in Table 1, the samples obtained in Examples 1 to 4 had a reduced surface free energy as compared with Comparative Example 1 without deteriorating the appearance. Furthermore, the samples obtained in Example 1 and Example 3 were superior in the ability to leave compared to Comparative Example 1.
In addition, as is clear from the comparison between Examples 1 to 4 and Comparative Examples 2 to 4, the molded article was compared with the case where only the fatty acid ester was added to the polyolefin by the combination of the silylated polyolefin and the fatty acid ester-based additive. Improved surface free energy, surface roughness, detachability and appearance.

Claims (5)

A resin composition comprising a thermoplastic resin, a silylated polyolefin, and a fatty acid ester having a molecular weight of 100 to 10,000. The resin composition according to claim 1, wherein the thermoplastic resin is a polyolefin. The molded object shape | molded from the resin composition of Claim 1 or 2. The molded body according to claim 3, wherein the molded body is a film or a sheet. The molded article according to claim 3 or 4, which is a container or a packaging material.