Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
  • D21H17/24—Polysaccharides
  • D21H17/28—Starch
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L35/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least one other carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J135/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least another carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Adhesives based on derivatives of such polymers
  • C09J135/06—Copolymers with vinyl aromatic monomers
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/35—Polyalkenes, e.g. polystyrene
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/36—Polyalkenyalcohols; Polyalkenylethers; Polyalkenylesters
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
  • D21H17/42—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups anionic
  • D21H17/43—Carboxyl groups or derivatives thereof

Definitions

• ABSTRACT A surface sizing composition for paper which comprises a copolymer of styrene and at least one unsaturated carboxylic compound selected from the group consisting of maleic acid, maleic anhydride and halfesters of maleic acid, wherein the copolymer has a carboxylate equivalent of 80 300 based on the free carboxylic acid form, and wherein the copolymer has 5 50% of its total carboxylic groups as alkali metal salts and 95 50% of its total carboxylic groups as at least one non-metal salt selected from the group consisting of ammonium salts and lower alkyl amine salts.
• This invention relates to surface sizing compositions for paper making. More particularly, this invention relates to stable surface sizing compositions which have excellent heat, mechanical and alum resistance during surface sizing.
• carboxylic group is intended to include carboxylate salts and the anhydride structure in addition of course, to the free carboxylic acid group.
• an anhydride group is the group which results from the condensation of two carboxylic groups.
• Paper is commonly surface-sized by means of a size press as follows: The paper sheet is semi-dried beforehand or is dried by driers positioned just before the size press runs through the dam of the sizing solution at a high speed. It is run between two press rolls under a high nip pressure, and then the treated sheet is dried by driers which are located just beyond the size press.
• Surface sizing has some advantages. For example, it leads to substantial savings in sizing costs and to improvement in paper quality compared to internal sizing techniques because almost all of the sizing composition is retained on the surface of the paper during surface sizing. During surface sizing by the size press, however, the sizing solution suffers heat and mechanical shock which is generated during the operation. In addition, aluminum salts such as alum elute from the paper into the sizing solution. These salts are used in the wet end of the sheeting step. These eluted salts have some adverse effects on the sizing solution because they facilitate precipitation of materials from the sizing solution. Because of the operational difficulties encountered in the sizing process, the sizing agent which is the main ingredient of the sizing solution should be stable to heat mechanical shock and be able to resist the aluminum salts in order to give the paper the proper amount of water resistance and writing quality.
• one object of this invention is to provide a surface sizing composition having improved properties.
• Another object of this invention is to provide a surface sizing composition having good stability under operating conditions.
• Yet another object of this invention is to provide a surface sizing composition which yields paper having improved properties at low cost.
• a surface sizing composition which comprises a copolymer of styrene and at least one unsaturated carboxylic compound selected from the group consisting of maleic acid, maleic anhydride and half-esters of maleic acid, wherein the copolymer has a carboxylate equivalent of 300 based on the free carboxylic acid form, and wherein the copolymer has 5 50% of its total carboxylic groups as alkali metal salts and 95 50% of its total carboxylic groups as at least one non-metal salt selected from the group consisting of ammonium salts and lower alkyl amine salts.
• the carboxylate equivalent of the copolymer as the free acid must be 80 300, preferably lOO 240. wherein the carboxylate equivalent means the molecular weight of the copolymer (reduced to the free acid basis) per carboxylate group.
• a copolymer with a value less than 80 exhibits inadequate sizing effects, while if the copolymer has a value greater than 300 the sizing effect and the solubility of the copolymer in water decreases.
• copolymers which have relatively low equivalents within the range of 80 to 300, because lower carboxylate equivalents bring about better solubility of the copolymer in water.
• carboxylate groups in the copolymer must be present in the form of specific salts in order to attain the objects of this invention.
• 5 50% of the total carboxylate groups must exist as an alkali metal salt, and 95 50% of the total carboxylate groups must exist in the form of at least one salt selected from the group consisting of ammonium salts and lower alkyl amine salts.
• the resulting copolymer does not have enough stability when used in the size press. If the copolymer has an alkali metal salt content greater than 50% the high salt content has an adverse effect on the sizing effects of the copolymer. When the sizing effects and the stability of the copolymer are considered it is preferred that the alkali metal salt be from 10 25%. However, if the stability characteristics of the copolymer are to be emphasized, it is preferable to use a copolymer having an alkali metal salt content within the higher regions of the 5 50% range.
• the copolymer also has a carboxylate group content as the ammonium and lower alkylamine salts preferably ranging from 75% of the total carboxylate group content.
• the copolymer preferably may also have a free carboxylate group content less than 45%, less than of the total carboxylate group content.
• Suitable alkali metal ions include sodium, potassium and mixtures thereof.
• Suitable lower alkyl C amine salts include salts of monomethyl amine, dimethyl amine, trimethyl amine, monoethyl amine, diethyl amine, triethyl amine and mixtures thereof. Mixtures of the ammonium salt and the lower alkyl amine salts may also be used.
• the preferred non-metal salts are ammonium salts and salts formed from amines having a molecular weight less than 60 and a boiling point less than C.(760 mmHg).
• the copolymer used in this invention can be produced by any one of several known methods.
• the copolymer is generally produced by copolymerizing styrene and an unsaturated carboxylic compound selected from the group consisting of maleic anhydride maleic acid and half esters of maleic acid in the presence of a solvent such as toluene, and then neutralizing the resulting copolymer to form the salts.
• the copolymer may be alternatively produced by just copolymerizing styrene and the salts of the unsaturated carboxylic compound.
• Half-esterification may be conducted after the styrene and maleic anhydride or maleic acid are copolymerized.
• Suitable alcohols for the esterification reaction include monohydric aliphatic alcohols containing 1 20 carbon atoms and having a straight or branched chain or an alicyclic ring.
• the preferred alcohols have straight or branched chains and contain 4 8 carbon atoms.
• the mole ratio of styrene to the unsaturated carboxylic compound is generally 30 90 70 l0, preferably 45 60 55 40.
• the copolymer of this inventin may contain one or more additional structural units.
• Suitable ethylenically unsaturated monomers as the third monomer, or structural unit include monomers containing carboxylic groups such as acrylic acid, methacrylic acid and fumaric acid; vinyl monomers such as vinyl acetate, vinyl chloride and a-olefins; acrylates and methacrylates such as methyl acrylate. methyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate and octyl acrylate; and other specific acrylic monomers such as acrylamide and hydroxyethyl acrylate.
• the third monomer may be present in molar amounts less than 60% preferably less than 40% of the total.
• the third monomer contains a carboxylic group, the group is included in the calculation of the carboxylate equivalent and the percentage of carboxylate groups in a salt the copolymer of the invention has a viscosity of at least 1000 cps. as a 40% by weight aqueous solution at 30C.
• the surface sizing composition of this invention may consist of the abovementioned copolymer alone.
• the copolymer is generally used with modifiers such as modified starches such as oxidized starches and enzyme converted starches, and polyvinyl alcohols.
• the weight ratio of the copolymer to the modifier may be 0.l 50 99.9 50.
• the copolymer may be also used with conventional sizing agents and other modifiers such as rosins and petroleum resins.
• the surface sizing composition of this invention may be applied to paper sheets by any conventional method.
• the sizing composition can be dissolved or dispersed in water to form a sizing solution (1 20% by weight), and then the solution is applied to a paper sheet by a size press, and the treated sheet is dried.
• the amount of the copolymer deposited on the paper is 0.0l 0.5g/m lsolid)". preferably 0.05 0.l5g/m (solidV.
• the amount of sizing composition deposited on the paper is l Sg/m (solid) preferably 2 3g/m (solid)?
• the surface sizing composition is used on various kinds of paper bases such as paper which contains a filler, water-leaf paper and soft-sized paper.
• the preferred paper is one which contains little or no internal sizing composition.
• the surface sizing composition of this invention has a good sizing effect and good stability in the sizing solution.
• the sizing solution containing the sizing composition of this invention, therfore, does not form a scum even under long and severe operating conditions in size presses.
• the viscosity was measured as a 40% by weight aqueous solution at 30C.
• the pH was measured as a 4% by weight aqueous solution.
• EXAMPLE 1 Into a four-necked, round-bottom 1000 cc. flask equipped with an agitator, a reflux condenser, a dropping funnel, a thermometer and a tube for the introduction of nitrogen gas, were charged 230.8g of methyl ethyl ketone, 1.0g of lauryl mercaptan, and 450g of maleic anhydride. The mixture was heated at reflux with stirring under a nitrogen atmosphere.
• the resulting copolymer had a carboxylate equivalent of I09, a viscosity of about 5000 cps., and a pH of 9.5.
• the copolymer had 10% of its total carboxylic groups in the form of the sodium salt and 90% in the form of the ammonium salt.
• Example l was repeated and a copolymer of the free carboxylic acid was obtained.
• the resulting copolymer was esterified with 29.6g of n-butyl alcohol to form a copolymer having a carboxylate equivalent of 256.
• the resulting copolymer was neutralized in the same manner as described in Example I whereby a 40% by weight aqueous solution of the copolymer was obtained which had 30% of the carboxylate groups as the sodium salt and of the carboxylate groups as the ammonium salt.
• the copolymer had a viscosity of 8000 cps. and a pH of 9.4.
• EXAMPLE 3 A copolymer was produced by the same method described in Example 1 using 178.2g of ethylene dichlo- 6 stead of the copolymer of this invention. Each of the sizing solutions was supplied to an inclined labo-size press by a handy pump. Outflow of the solution waS recycled. The stability was determined by observing the ride, 1.2g of lauryl mercaptan, 540g of maleic anhy- 5 formation of scum every 30 minutes. Operational condride, 50.4g of styrene, 15.6g of n-butyl acrylate and ditions were as follows: 0.6g of 2,2'-azobisisobutyronitrile. The solution was 1.
• Example 3 Example 4 No scum developed in the pressing operation for more than 8 hours.
• Example 5 B Styrene-maleic anhydride copolymer Substantial developement of scum in the pressing operation after 3.0 3.5 hours.
• EXAMPLE 6 (Test of Stability) A stability test was conducted with each of the sizing solutions prepared from the copolymer solutions produced in Examples 1 5.
• An aqueous sizing solution (5,000 cc) was prepared which contained 0.8% by weight of each of the copolymers of the invention and 7.2% by weight of an oxidized starch.
• an aqueous sizing solution was prepared using conventional sizing agents in- EXAMPLE 7 (Test of the sizing effects) A test of the sizing effects was made on each of the copolymers produced in Examples l 5 in comparison to some conventional sizing agents.
• Base paper Paper was produced by sheeting pulp L-BKP.
• the pulp had a degree of beating of 420 contained clay (filler) and a fortified rosin (internal sizing agent) at a pH of 4.5 (adjusted with alum).
• the resulting paper had a weight of 60 62g/m with an ash content of 13.0% and a rosin content of 0.09% by weight.
• IGT surface strength was determined by the method of .l. Tappi Standard T 499 Su-64. Surface strength of Paper (lGT Tester].
• a surface sizing composition for paper which comprises:
• a copolymer of styrene and at least one unsaturated carboxylic compound selected from the group consisting of maleic acid, maleic anhydride and half esters of maleic acid wherein said copolymer has a carboxylate equivalent of 80 300 based on the free carboxylic acid form, and wherein said copoly mer has 5 50% of its total carboxylic groups as alkali metal salts and 95 50% of its total carboxylic groups as at least one non-metal salt selected from the group consisting of ammonium salts and lower alkyl amine salts.
• alkali metal salt is the sodium salt or potassium salt.
• the surface sizing composition of claim 1 wherein the copolymer has an additional structural unit derived from an ethylenically unsaturated monomer 11.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Paper (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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Cited By (21)

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Citations (5)

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• 1972
  • 1972-11-15 JP JP11507872A patent/JPS5325049B2/ja not_active Expired
• 1973
  • 1973-11-02 US US412350A patent/US3925328A/en not_active Expired - Lifetime
  • 1973-11-08 SE SE7315177A patent/SE408313B/xx unknown
  • 1973-11-12 FI FI3482/73A patent/FI56228C/fi active
  • 1973-11-12 GB GB5247173A patent/GB1433190A/en not_active Expired
  • 1973-11-13 FR FR7340238A patent/FR2206406B1/fr not_active Expired
  • 1973-11-14 IT IT70348/73A patent/IT996966B/it active
  • 1973-11-15 DE DE2357165A patent/DE2357165B2/de not_active Ceased
  • 1973-11-15 CA CA185,885A patent/CA989529A/en not_active Expired

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