CS195937B1 - Polymer dispersion for kraft paper impregnation - Google Patents

Abstract

The invention relates to a polymer dispersion of vinyl acetate — butyl acrylate — glycol maleate, intended for impregnation of kraft paper, further used as a raw material in the production of sandpaper. Sandpaper impregnated with the above dispersion has excellent mechanical and physical properties, especially when used wet. This property is of decisive importance, affecting the service life of the paper, in the main area of application — in the grinding of automobile bodies.

Description

CZECHOSLOVAK SOCIALISTIC

(19)

INVENTORY OFFICE DISCOVERY

DESCRIPTION OF THE INVENTION

TO OSWDtEHIII (22) Entries 24 02 77 (21) (PV 1229-77) (40) Published 29 QS 79 (45) Published 15 06 82 (11) (51) Int. Cl.1 2 3C 08 F 2/24 (B1) (75) _ '.

Author of the invention KUKÁ IGOR ing., MOLDA EMIL ing., ONDRUŠ ŠTEFAN ing., BUDAY MIKULÁŠ ing., FRÁŇO EUDOVÍT ing., ŠALA, MORAVOVÁ JARMILA ing., PRAHA and HANČIL JAROSLAV ing., SVOBODA nad Úpou (54) Polymer dispersion on impregnating kraft paper 1

BACKGROUND OF THE INVENTION The present invention relates to a polymeric dispersion of vinyl acetate-butyl acrylate-glycol maleate for impregnating kraft paper used as a raw material in the manufacture of abrasive paper. The abrasive paper impregnated with said dispersion has excellent mechanical and physical properties, most notably wet use. This feature has a decisive influence on the life of the paper, in the field of application - in car body sanding.

For impregnating and refining paper, several systems based on synthetic polymer emulsions are patented. Very common is the use of melamine-formaldehyde resins, which increase the physical-chemical properties of the paper, mainly wet strength (USSR Pat. No. 370,319), mechanical strength and water resistance (Fr. 2 219 200, NSR Pat. 2,241,129). They use solitary, possibly modified with sulfur sulphides (Fr. 2 213 373).

The use of acrylonitrile to increase the strength of the paper (U.S. Pat. No. 2,948,999) or a two-component system based on urea-formaldehyde resin and hardener (U.S. Pat. No. 4,890,894) is described. The polymer prepared from a mixture of styrene polymers or acrylonitrile and an acrylate ester or methacrylate with an alcohol containing 2-6 carbon atoms is described in NSR Pat. 1 546 236. NSR Pat. This dispersion has a crosslinking ability at temperatures above 100 ° C.

English Patent 1 342 315 recommends impregnating paper in a reaction product of polyamide resin and epi- and / or chlorohydride (as well as U.S. Pat. No. 3,772,076). For surface treatment of paper-polymers of styrene and maleic anhydride. The USSR recommends increasing the hydrophobicity, elasticity and strength of sulphate-free cellulose-based paper. 318 656 di-vinylstyrene, divinylnitrole, respectechloroprene latex.

The use of a terpolymer, vinyl acetate-butyl acrylate-glycol maleate, to impregnate paper to improve its mechanical-physical properties is not described in the literature. The impregnation systems used so far are based on another polymeric base. They are used abroad in the construction of emulsion terpolymers such as vinyl acetate-butyl acrylate-vinyl laurate and vinyl acetate-butyl acrylate-vinyl chloride.

The principle of the terpolymer dispersion according to the invention is that an emulsion polymer prepared by emulsion polymerization of vinyl acetate with butylacyl-195937 195937 rylate and a monoethylene glycol maleate in a ratio of 60-70 to 2-5% by weight is used for impregnation. under atmospheric pressure in an aqueous medium characterized by a dry weight of 50-53% by weight, a viscosity of 20-100 mPa. with a pH of 3.5-6, a residual monomer of at most 1% by weight, a particle size of 100-200 nm and a 100% colloidal dilution stability. The basic properties of the resulting emulsion polymer are in the first row dependent of the monomer used and the monomers respectively. By varying the composition of the emulsion system and, ultimately, by the changes in the technological process of preparation, such as the addition method, the feed rate, the polymerization temperature, we add the initiator, the reaction procedure, and others to modify the properties of the resulting emulsion. product.

With the given composition of the polymerization composition and the preparation process, we get dispersions specific to the rolling parameters. The dispersed emulsion system, i.e., the combination of emulsifiers and protective colloids, also depends on the basic dispersion properties, such as viscosity, particle size, and particle size distribution. A summary of these properties predetermines dispersion for a particular application.

Sulfonated, nonionic and nonionic surfactants are used as emulsifiers for the preparation of dispersions. Of the anionic emulsifiers, sulfonates, alkyl sulfates, ethoxylated sulfates and ethoxylated alkyl phosphates are most commonly used. Of the nonionic types, the ethoxylated alcohols and alkylphenols and the block copolymers are ethylene oxide-propylene oxide. The present invention relates to an emulsion polymer of vinyl acetate-butyl acrylate-ethylene glycol maleate prepared using an emulsion system consisting of an alkylpolyglycol ether phosphate and a block copolymer ethylene oxide propylene oxide. The third comonomer (monoethylene glycol maleate) is the main component that determines the quality of the resulting polymer and, in particular, its impregnation ability. It introduces a reactive OH group into the polymerization chain, capable of forming hot crosslinked structures with other substances. A dispersion prepared without its use is not suitable for impregnating paper.

The dispersion of the present invention is a low viscosity viscosity of 20-100 mPas, fine dispersion with an average particle size of 100-200 nm, excellent mechanical and colloidal stability (100% for 14 days and resistance to electrolytes. Film solubility in water). in 24 hours, 5% by weight, strength 294.2104 Pa, elongation 1100 mm, and the third comonomer (mono-ethylene glycol maleate) from the maleic anhydride and ethylene glycol molar ratios of 1: 1 must be prepared prior to the actual polymerization. The resulting product is a high viscosity liquid characterized by an acid value of about 350 mg KOH / g, while storing under atmospheric conditions to form chemical changes, while the resulting water content of the product is maintained at room temperature for 2 hours. Monoethylene glycol maleate with a water content above 3 - 3.5% by weight is suitable for the preparation of a dispersion. The shelf life and composition of the product is to use a molar ratio of starting ingredients of 2: 1. In this case, the product characterized by an acid number of 250 mg / KOG / g and a viscosity of 240 mPAS. The qualitative parameters of the dispersion and its impregnation properties are the same as in the case of using a glycol maleate prepared from 1: 1 ratios.

Sodium alkyl polyglycol polyether phosphate has proven to be a suitable emulsifier for a given application. It is recommended to use 0.8 - 2.4% by weight. for a mixture of monomers, preferably at a concentration of 1.03 wt. In combination with the sodium polyglycol ether phosphate, the use of an acrylic acid addition product with an ethylene oxide-propylene oxide block copolymer is recommended. This preparation consists of two phases: a) bleaching of ethylene oxide-propylene oxide copolymer b) self-preparation

The bleaching of the copolymer is carried out with hydrogen peroxide at 80 ° C for 40 minutes. Thereafter, continuous dosing of acrylic acid lasting 2 hours is started. At the beginning of the dosing of acylic acid, a solution of potassium perborate is added. After charging the acrylic acid solution, the product is reacted at 90 ° C. The product prepared is a yellow-green, clear, viscous liquid with an active ingredient content of 60%. The product is used in the range of 3 to 5 wt. to a monomer mixture typically of 3.7% by weight. Copolymer-ethylene oxide-propylene oxide alone can also be used in combination with alkyl polyglycol ether. In this case, higher concentrations in the composition are required in the amount of 5.1 to 6.2% by weight. nasmes monomers.

Sodium carbonate (0.41% by weight) is recommended as a buffer for controlling the pH of the polymerization. The resulting pH of the dispersion is in the range of 4 to 4.1. EXAMPLE 1 Prepare a water phase in a polymerization flask by mixing water, an alkyl polyglycol ether-sodium phosphate, an acrylic acid addition product with an ethylene oxide-propylene oxide-sodium carbonate copolymer. A 20% solution is withdrawn from the aqueous phase and a 5% peroxodisulfate solution is added.

Claims (2)

Thus prepared a third comonomer mixture prepared for dispensing into a polymerization apparatus. The residual aqueous phase is eluted to 6% PC, the initiator solution is added. After the initiator was added, the vinyl acetate / butyl acrylate monomer mixture was continuously charged. After dispensing about 25% of the mixture, a third comonomer is continuously metered in. Its dosage ends 10 minutes before the end of dosing of the monomer mixture, which lasts for 140 minutes. The dispersion reacts at 85 ° C for 10 minutes. The prepared dispersion has a viscosity of 20-60 mPa. s, residual mono- mer content 0.6-0.8% by weight, pH '3.8-3.9, 110 nm particle size, colloidal stability 100% vol. after 14 days. Example The preparation process is the same as in Example 1 except that the same block copolymer is used instead of the addition product of acrylic acid and the ethylene oxide-propylene oxide copolymer at a concentration of 3.7% by weight. to a mixture of monomers. The quality of the dispersion is the same as in Example 1. OBJECT Polymer dispersion for the impregnation of polyvinyl acetate-based sulphate paper containing 50 to 53% by weight. dry matter with a viscosity of 20 to 100 mPa. with a pH of 3.5 to 6 with a residual monomer of max. 100 to 200 nm and 100% colloidal dilution stability, prepared by emulsion polymerization of vinyl acetate, butylacrylate and monoethylene glycol maleate in a ratio of 65 to 70 to 25 to 30 to 2 to 5% by weight. under atmospheric pressure in an aqueous medium at a temperature of 75 ± 2 ° C, wherein the emulsion system consists of sodium polyglycol ether phosphate of 0.8 to 2.4% by weight per mixture of monomers and acid addition product with copolymer ethylene oxide-propylene oxide or copolymer ethylene oxide-propylene oxide alone in an amount of 3 to 5% by weight of the mixture of monomers and buffer, which is sodium bicarbonate in an amount of 0.2 to 0.6% by weight. to a mixture of monomers. Severografia, n. P., Zftvod 7, Most