OIL-RESISTANT AGENT FOR PAPER

1 . A paper oil-resistant agent which is added to interior of paper, comprising:

(1) a fluorine-free polymer, and

(2) at least one type of particles selected from inorganic particles or organic particles,

wherein an amount of the particles (2) is 1 to 99.9% by weight, based on the total weight of the fluorine-free polymer (1) and the particles (2).

2 . The paper oil-resistant agent according to claim 1 , wherein the fluorine-free polymer (1) is an acrylic polymer.

3 . The paper oil-resistant agent according to claim 1 , wherein the fluorine-free polymer has a repeating unit formed from (a) an acrylic monomer having a long-chain hydrocarbon group, and

the acrylic monomer having a long-chain hydrocarbon group (a) is a monomer represented by formula:

CH 2 ═C(—X 1 )—C(═O)—Y 1 (R 1 ) k

wherein

R 1 each is independently a hydrocarbon group having 7 to 40 carbon atoms,

X 1 is a hydrogen atom, a monovalent organic group, or a halogen atom,

Y 1 is a divalent to a tetravalent group composed of at least one selected from a hydrocarbon group having one carbon atom, —C 6 H 4 —, —O—, —C(═O)—, —S(═O) 2 —, or —NH—, provided that a hydrocarbon group is excluded, and

k is 1 to 3.

4 . The paper oil-resistant agent according to claim 3 , wherein, in the acrylic monomer having a long-chain hydrocarbon group (a), X 1 is a hydrogen atom or a methyl group.

5 . The paper oil-resistant agent according to claim 3 , wherein, in the acrylic monomer having a long-chain hydrocarbon group (a), the long-chain hydrocarbon group has 18 or more carbon atoms.

6 . The paper oil-resistant agent according to claim 3 , wherein

the acrylic monomer having a long-chain hydrocarbon group (a) is:

(a1) an acrylic monomer represented by formula:

CH 2 ═C(—X 4 )—C(═O)—Y 2 —R 2

wherein

R 2 is a hydrocarbon group having 7 to 40 carbon atoms,

X 4 is a hydrogen atom, a monovalent organic group, or a halogen atom, and

y 2 is —O— or —NH—, and/or

(a2) an acrylic monomer represented by formula:

CH 2 ═C(—X 5 )—C(═O)—Y 3 —Z(—Y 4 —R 3 ) n

wherein

R 3 each is independently a hydrocarbon group having 7 to 40 carbon atoms,

X 5 is a hydrogen atom, a monovalent organic group, or a halogen atom,

Y 3 is —O— or —NH—,

Y 4 each is independently a group composed of at least one selected from a direct bond, —O—, —C(═O)—, —S(═O) 2 —, or —NH—,

Z is a direct bond or a divalent or trivalent hydrocarbon group having 1 to 5 carbon atoms, and

n is 1 or 2.

7 . The paper oil-resistant agent according to claim 3 , wherein

the acrylic monomer having a hydrophilic group (b) is at least one oxyalkylene (meth)acrylate represented by formula:

CH 2 ═CX 2 C(═O)—O—(RO) n —X 3   (b1)

CH 2 ═CX 2 C(═O)—O—(RO) n —C(═O)CX 2 ═CH 2   (b2), or

CH 2 ═CX 2 C(═O)—NH—(RO) n —X 3   (b3)

wherein

X 2 is a hydrogen atom or a methyl group,

X 3 is a hydrogen atom or an unsaturated or saturated hydrocarbon group having 1 to 22 carbon atoms,

R each is independently an alkylene group having 2 to 6 carbon atoms, and

n is an integer of 1 to 90.

8 . The paper oil-resistant agent according to claim 3 , wherein the fluorine-free polymer further comprises a repeating unit formed from (c) a monomer having an olefinic carbon-carbon double bond and having an anion donating group or a cation donating group, other than the monomers (a) and (b).

9 . The paper oil-resistant agent according to claim 8 , wherein the anion donating group is a carboxyl group, or the cation donating group is an amino group.

10 . The paper oil-resistant agent according to claim 3 , wherein an amount of the repeating unit formed from the acrylic monomer having a long-chain hydrocarbon group (a) is 30 to 90% by weight, based on a copolymer, and an amount of the repeating unit formed from the acrylic monomer having a hydrophilic group (b) is 5 to 70% by weight, based on the copolymer.

11 . The paper oil-resistant agent according to claim 1 , wherein the inorganic particles are made of at least one selected from calcium carbonate, talc, kaolin, clay, mica, aluminum hydroxide, barium sulfate, calcium silicate, calcium sulfate, silica, zinc carbonate, zinc oxide, titanium oxide, bentonite, and white carbon, and the organic particles are made of at least one selected from polysaccharides and thermoplastic resins.

12 . The paper oil-resistant agent according to claim 1 , wherein the organic particles are insoluble in water at 40° C.

13 . The paper oil-resistant agent according to claim 1 , wherein the inorganic particles are calcium carbonate, and the organic particles are starch.

14 . The paper oil-resistant agent according to claim 1 , wherein the particles (2) comprises the organic particles.

15 . The paper oil-resistant agent according to claim 1 , further comprising a liquid medium which is water or a mixture of water and an organic solvent.

16 . Oil-resistant paper comprising the paper oil-resistant agent according to claim 1 , in interior of the paper.

17 . The oil-resistant paper according to claim 16 , which is a molded pulp product.

18 . The oil-resistant paper according to claim 16 , which is a food packaging material or a food container.

19 . A method for producing oil-resistant paper, comprising:

preparing a formulated pulp slurry by adding the oil-resistant agent according to claim 1 to a slurry in which pulp is dispersed in an aqueous medium, making an oil-resistant paper intermediate, followed by dehydrating and then drying to obtain the oil-resistant paper.