SU439496A1 - Paper Coating Compound - Google Patents

Description

one

The invention relates to the field of plastics processing, to the preparation of compositions for coating paper intended for packaging products containing aromatic substances (pepper, coffee, vanilla, etc.) and fats, household chemicals and sanitary napkins, "soaked" roasting and flavored composition.

A paper coating composition is known that contains an aqueous dispersion of a copolymer of vinylidene chloride with vinyl chloride and butyl acrylate.

The coating does not provide a sufficiently low permeability of water vapor, it becomes sticky and has a ca.x.

The purpose of the invention is the development of a composition for coating packaging paper, which provides for the preparation of packaging material impermeable to gases, aromatic substances, fats and capable of thermally gluing on automatic machines.

According to the invention, an aqueous dispersion of a copolymer of vinylidene chloride and vinyl chloride is used with a content of Z3-37% vinyl chloride units, additionally containing methylcellulose (viscosity more than 100 rpm) and tulimethylsiloxane liquid with a kinematic viscosity of 200-400 eats, for example, PMS-200 or PMS -40-0, with the following ratio of components, weight. including:

Co-polymeric vinylidenechloride - with vinyl chloride containing 33-37% wine-ilchloride units 45-50

Methylcellulose 0.1-0.1

Polymethylsiloxane liquid 0,01-0,02

Water 60-56

Example. In the dispersion of the finished copolymer containing 63--67% vinylidene chloride and 33-37% vinyl chloride, with constant vigorous movement, is gradually introduced first with an aqueous solution of methylcellulose

(MC), and then 1-polymethylsilox-new liquid (PMS). After the introduction of the MC and PMS, the dispersion should be kept for 2-3 hours to ripen. Before methylcellulose is introduced into the copolymer dispersion, it is (Pre-soaked to swell in cold demineralized water at the rate of 2 g of absolutely dry methylcellulose, for example, МЦ-100 (ТУ В-62-69), 98 g of demineralized water in

for 10-12 hours, then mechanically stirred and the resulting viscous solution is introduced into the dispersion of the finished copolymer. The dispersion coating is applied to the base paper with a sizing of not less than 1.75 mm and a smoothness of 200-300 seconds on machines equipped with

air drier, infrared drying zones and underfloat coating.

To impart high protective properties to paper, it is necessary to have a coating of at least 25 microns thick (two to three times application).

As a result of the film-forming process that occurs during drying, the protective coating of vinylidene chloride copolymer gives the packaging paper a number of valuable properties: impermeability to gases, aromatic substances, water vapor and fats, as well as thermal adhesion. The coating is non-toxic, non-sticky and odorless.

paper properties with

Physicomechanical coating.

Thickness, mkm

Water vapor permeability, g / m, for 24 hours (. T 22C...

Permeability:

for fat

for aromatic substances

Water tightness, hour (DL 500mm waters, art.)

Gas permeability. Cm (cm) / (cm) sec. Atm-10 °:

for oxygen ....

for carbon dioxide

Gluing temperature, ° C. .

Subject invention

A paper coating composition containing an aqueous dispersion of a copolymer of vinylidene chloride with vinyl chloride, characterized in that, in order to improve the quality of the coating, a copolymer of vinyl lenechloride with vinyl chloride with a content of vinyl chloride units of 33-37% is used as the copolymer; 200-400 eats and methylcellulose and the components are taken in the following ratio, wt. h .: Copolymer of vinylidene chloride with

vinyl chloride content of vinyl chloride links E e-37% 45-50

Polymethylsiloxane

LIQUID 0,01-0,02

Methylcellulose 0.1-0, G5

Water 50-S5