# US 5,341,672 A · Method for measurement of polymer molecular weight based upon a temperature difference

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- Number: US 5,341,672 A
- Document ID: US5341672A
- Status: Granted
- Kind: A
- Application number: 08/155,657
- Filed: 1993-11-22
- Granted: 1994-08-30
- Earliest claimed: 1991-04-22
- Assignees: Kanegafuchi Chemical Industry Co., Ltd.; Snow Brand Milk Products Co., Ltd.
- Inventors: Norio Kawanami; Kiyotaka Kondo; Yoshihiro Ikeda; Tooru Nakagawa; Kensuke Itoh; Yukihiro Saiki; Saburo Ishii; Kenji Aoyama
- Web page: https://patentgrep.com/patent/US5341672A

## CPC

- G01N 33/442: {Resins; Plastics}
- G01N 25/18: by investigating thermal conductivity (by calorimetry G01N25/20; by measuring change of resistance of an electrically-heated body G01N27/18)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A molecular weight of a polymer is measured by a process including steps of: heating a polymer portion with a heating device, measuring, with a temperature measuring device, the difference between temperatures of at least two points of the polymer portion at each of which the polymer portion is subjected to a thermally different influence from each other by the heating device, and estimating the molecular weight of the polymer which corresponds to the difference between the temperatures obtained by the measuring step according to a relationship between the temperature difference and the molecular weight of the polymer which relationship has been beforehand obtained.

## Claims

### Claim 1

A method for the measurement of a molecular weight of a polymer during a present polymerization thereof which comprises the steps of:
heating a polymer portion with heating means,
measuring, with temperature measuring means, a difference between temperatures of at least two points of the polymer portion thereby determining an empirical point, each of said points being thermally influenced by said heating means differently from the other of said points, and
establishing the molecular weight of the polymer which corresponds to the difference between the temperatures obtained by the measuring step according to a predetermined relationship between the temperature difference and the molecular weight of the polymer, wherein
the predetermined relationship is obtained by first obtaining a calibration curve between the temperature difference and the molecular weight of the polymer in an earlier polymerization process, and then moving the calibration curve in parallel, while maintaining the shape of the calibration curve, so that the curve contains said empirically determined point measured during the present polymerization.

### Claim 2 (depends on 1)

The method according to claim 1 wherein the heating means also works as the temperature measuring means which measures the temperature at one point of the at least two points.