CS204243B1 - Method of making the tubes from the non-plasticized pvc with permitted tangent tension sigma bol'sche chem 12,5 - Google Patents

Description

The invention relates to a process for the manufacture of polyvinyl chloride-based pipes with a permissible tangential stress of sigma «12.5 MPa, in particular by extrusion technology.

The process for producing pipes with a permissible tangential stress of sigma 6 MPa and sigma 10 MPa is known. For this purpose PVC with a K-value of 65 to 68 is used, which is mixed with the necessary additives, in particular stabilizers, lubricants, possibly fillers and pigments. The mixture thus prepared is either directly extruded on an extruder or granulated, and then extruded on an extruder. Extruders are also used which only granulate the powder mixture in the first phase and displace the granules in the next phase. The shape and dimensions of the pipe are determined by the shape and dimensions of the die ring.

The disadvantage of such a process of PVC tubes production is that even small fluctuations in PVC quality, additive system, in the preparation of the mixture, as well as the actual technological processing cause a decrease of PVC tubes quality and do not allow production of PVC tubes with permissible tangential stress of sigma 12.5 MPa.

According to the present invention, these disadvantages can be eliminated and the mechanical properties of the PVC pipes produced can be significantly improved.

According to the invention, pipes of non-crimped PVC 8 with a permissible tangential stress of 12.5 MPa are produced in such a way that a PVC mixture having a K-value of 6767, preferably Si 70 and 8, preferably having a particle size of 0.250 mm to 0.063 mm extruder extractors which are housed in a chamber heated and regulated externally to a temperature range of 150 to 220 ° C and equipped with a degassing zone, extruded through a heated extruder head through a nozzle at a pressure of 20 to 45 MPa, and the pipe is drawn through at a temperature of 5 to 34 ° C, at the same rate as the extrusion speed.

According to the present invention, polyvinyl chloride is used for the production of pipes with a permissible tangential stress of sigma 12.5 MPa, which, in addition to the above-mentioned properties, contains volatile fractions of 0.05-0.3% by weight, sulfur ash in an amount of 0.01-0.2 By weight, the pH of the aqueous extract is 6-9, with a high bulk density and a low impurity content.

PVC is used as an additive material for the production of pipes according to the invention, which may be, for example, auapausal or block, as stabilizers preferably used basic sulphates and / or basic and neutral lead stearates, or tin mercapides such as calcium stearate, paraffin stearic acid and polyethylene wax as a filler, for example, surface-treated calcium carbonate and, if necessary, small amounts of pigments of organic and / or inorganic origin, the blend polymer being mixed until the temperature reaches a maximum of 165 ° C and subsequently cooled to e.g. 40 ° C to 50 ° C ·

The advantage of the above-mentioned pipe production process compared to the hitherto used is the increased value of the permissible tangential stress of the pipes, which makes it possible to reduce the wall thickness of the pipes and thus to save material for their production.

Example 1

A dry blend of 100 parts by weight of suspension PVC with a K-value of 70, a sieve retention of 0.250 mm 0.2% by weight and a mesh of 0.063 mm 99% by weight and a volatile fraction content of 0.03% by weight is prepared on a high-speed fluidized bed mixer. a sulphated ash content of 0.01 wt.%, an aqueous extract pH of 6.5, a bulk density of 620 kg / m @ 2 and an impurity content of 3 per 10 g, 2.2 wt. 2 parts by weight of a stabilizer comprising basic sulphates and lead stearates and calcium stearate and paraffin-based lubricants; parts by weight of calcium carbonate filler and 0.01 wt. parts of carbon black as a pigment. The mixture was stirred to 120 ° C and then cooled to 40 ° C. The finished blend is made by extrusion on a twin screw extruder by dosing the blend with a screw feeder for rotating extruder worms that are housed in an outside chamber heated by electrical resistors and controlled by controllers, with the temperature of the individual bands being 160 °. C, 175 ° C, 185 ° C, 170 ° C, 170 ° C, 170 ° C, 175 ° C, 185 ° C starting from the hopper. The blend blended in these bands is extruded through a die formed by a die and a prong at a die temperature of 190 ° C and the pipe is drawn through a tempered caliber at 18 ° C at the same rate as the extrusion rate.

The polymer melt temperature is kept constant at 215 ° C. The pipes thus prepared are characterized by a yield strength of 56.9 MPa and an internal overpressure resistance at a tangential stress of 21 MPa at a wall temperature of 60 <> C for 35 hours and at a tangential stress of 14 MPa at a temperature of 60 ° C more than 1,100 hours.

Example 2

A dry blend of 100 wt. % of suspension PVC with a K-value of 72, with a sieve retention of 0.250 mm, 9.5 wt. and on a 0.063 mm sieve 95.5 wt. and having a volatile fraction of 0.13% by weight, a sulphated ash content of 0.15, a pH of an aqueous extract of 6.8, a bulk density of 555 kg / m &lt; 2 &gt; 2 parts by weight of a stabilizer comprising basic sulphates and lead stearates, calcium stearate and paraffin-based lubricants; parts of calcium carbonate and 0.01 wt. parts of carbon black as a pigment. The mixture was stirred until 140 ° C was reached, and then ea was cooled to 50 ° C. The finished mixture is made by extrusion on a twin screw extruder as in Example 1, wherein the extruder chamber is equipped with a degassing zone with a vacuum of 61 kPa and the extruder zone temperatures are controlled so that the melt temperature is constant at 195 ° C. The temperatures of the tool bands are set in each zone towards the nozzle 160 ° C, 170 ° C, 175 ° C, 195 ° C, 185 ° C, and at the nozzle .190 ° C. The pipes prepared in this way are characterized by a cross-sectional strength of 54.2 MPa and an internal overpressure resistance at a tangential stress of 21 MPa at a wall temperature of 60 ° C for 15 hours and at a tangential stress of 14 MPa at a temperature of 60 ° C 1,100 hours.

Example 3 j

On the. A dry blend of 100 wt. % parts of block PVC with a K-value of 75, with a mesh retention of 0.250 mm 0.1 wt. and on a 0.063 mm sieve 90 wt. and having a volatile fraction of 0.07 wt.%, with a sulphated ash content of 0.02 wt.%, a pH of an aqueous extract of 6.45 with a bulk density of 577 kg / m @ 2 and an impurity content of 10 pcs / 10 g. 8 wt. 2 parts by weight of a stabilizer comprising basic sulphates and lead stearates, calcium stearate and paraffin-based lubricants; parts of calcium carbonate and 0.01 parts by weight of carbon black as pigment. The mixture was stirred to 110 ° C and then cooled to 40 ° C. The finished mixture is made into an oven by extrusion to. of a twin-screw extruder as in Example 1, wherein the temperatures of the extruder bands are controlled so that the melt temperature is constant at 222 ° C.

The temperatures of the tool bands are set in individual zones towards the nozzle 165 ° C,

165 ° C, 170 ° C, 200 ° C, 190 ° C, and on a nozzle 200 ° C. The pipes prepared in this way are characterized by a cross-section strength of 57.2 MPa and an internal overpressure resistance at a tangential stress of 14 MPa at a wall temperature of 60 ° C for 1,100 hours.

Example 4

A 100 wt.% Dry mix is prepared in a high-speed fluidized bed mixer. 0.3 parts by weight of PVC according to Example 1; 0.5 parts by weight of dimethyl tin mercaptide as a stabilizer; parts by weight of calcium stearate, 0.3 wt. parts by weight of polyethylene wax based lubricant and 0.4 wt. parts by weight of paraffin wax based lubricant, 2 wt. % calcium carbonate and 0.01 wt. parts of carbon black as a pigment. The mixture was stirred until a temperature of 120 ° C was reached and then cooled to 40 ° C. The finished mixture is made by extrusion on a twin screw extruder as in Example 1, at temperatures of 170 ° C, 175 ° C, 185 ° C, 165 ° C, 155 ° C, 170 ° C, 170 ° C,

190 ° C, 180 ° C set in each machine zone, starting from the hopper and on the 190 c> C nozzle.

The polymer melt temperature is maintained at a constant temperature of 200 ° C. Pipes prepared in this way are characterized by a cross-section strength of 53.1 MPa and resistance to internal overpressure, at a tangential stress in the wall of the oven of 21 MPa at 60 ° C for 8 hours and at a tangential stress in the wall of the oven of 14 MPa and 60 ° C for 425 hours .

Claims (1)

No. 3,204,243 denote a cross-sectional strength of 54.2 MPa and a resistance to internal overpressure at a tangential tension in the pipe wall of 21 MPa and a temperature of 60 ° C for more than 15 hours and at a tangential tension in the wall of 14 MPa and a temperature of 60 ° C. than 1 100 hours. Example 3 j Na. a dry mix of 100 wt. parts of block PVC with a K-value of 75, with a retaining of 0.250 mm 0.1% by weight. and on the sieve 0,063 mm 90 Material. and with a volatile content of 0.07 wt%, with a sulphated ash content of 0.02 wt%, with a pH of an aqueous extract of 6.45 with a bulk density of 577 kg / m 2 and an impurity content of 10/10 g, 1, 8hmotn. parts of a stabilizer comprising basic sulphates, and lead stearates, calcium stearate and paraffin-based lubricants, 2 wt. parts of calcium carbonate and 0.01 parts by weight as pigment. The mixture is stirred until a temperature of 110 ° C is reached and then cooled to 40 ° C. An oven is made from the finished mixture by extrusion. with a twin screw extruder as in Example 1, wherein the temperatures of the extruder bands are controlled such that the melt temperature is constant and is 222 ° C. Tool zone temperatures are set in individual zones toward the nozzle at 165 ° C, 165 ° C, 170 ° C, 200 ° C, 190 ° C, and at a nozzle of 200 ° C. The pipes thus prepared are characterized by a cross-sectional strength of 57.2 MPa and a resistance to internal overpressure at a tangential tension of the pipe wall of 14 MPa and a temperature of 60 ° C for 1100 hours. EXAMPLE 4 A dry mix of 100 wt.% Is prepared on a high speed fluid mixer. parts of PVC according to Example 1, 0.3 wt. parts of dimethyltin mercaptide as stabilizer, 0.5 wt. % calcium stearate, 0.3 wt. parts of polyethylene wax based lubricant and 0.4 wt. paraffin wax based lubricant, 2 wt. parts of calcium carbonate and 0.01 parts by weight of carbon black as pigment. The mixture is stirred until a temperature of 120 ° C is reached, and then cooled to 40 ° C. From the finished mixture, an oven is produced by extrusion on a twin-screw extruder as in Example 1, at temperatures of 170 ° C, 175 ° C, 185 ° C, 165 ° C, 155 ° C, 170 ° C, 170 ° C, 190 ° C, 180 ° C set in individual machine zones, starting from hopper and to nozzle 190 c> C. The polymer melt temperature is kept constant at 200 ° C. The pipes prepared in this way are characterized by a cross-sectional strength of 53.1 MPa and a resistance to internal overpressure, a preloaded tension in the pipe wall of 21 MPa and a temperature of 60 ° C for 8 hours, and a tangential tension of the tube of 14 MPa and a temperature of 60 ° C for 425 hours. . OBJECT OF THE INVENTION A method of producing non-creased PVC tubes with permissible tangential tension of sigma ~ 12.5 MPa, characterized in that the PVC mixture of K value = 6767 is preferably 70 and preferably of large particle size 0.250 mm to 0.063 is screwed onto the rotating the extruder screws, which are housed in a chamber, externally heated and controlled to a temperature in the range of 150 to 220 ° C and provided with a degassing zone, are extruded through a heated extrusion head at a pressure of 20 to 45 MPa, and the oven is drawn off through tempered caliber with a temperature of 5 to 34 ° C, at a rate equal to the extrusion speed. Srvfropafia. η. p- civod 7. Moct