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Controlled Particle Size Distribution

A technology of particles and aggregates, applied in the field of controlled particle size distribution, which can solve the problem that particles cannot be effectively packed

Active Publication Date: 2021-10-26
DDP特种电子材料美国有限责任公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage associated with a uniform distribution is that in an aggregate of spherical particles all of the same size, the particles cannot pack efficiently to fill a volume of space

Method used

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  • Controlled Particle Size Distribution
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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0074] Example 1: Preparation of a multimodal distribution

[0075] A suspension of droplets suspended in an aqueous medium was prepared using the procedure as described in US 4,444,960, having the particle size set as described below.

[0076] A monomer mixture comprising 83.9 parts by weight styrene, 15.8 parts by weight divinylbenzene (a mixture of 63% divinylbenzene and 27% ethylvinylbenzene) and 0.17 parts by weight peroxide initiator was passed through an orifice plate ( The plate had two openings (the dimensions of which are specified in the table below)) into the monomer reservoirs in four different sequential conditions listed in the table below for a total of 97 minutes. As defined in US 4,444,960 and using Reynolds numbers and Strouhal numbers.

[0077]

[0078] The first 20 minutes of operation produced an aggregate "A" of monomer droplets. Then, only the Strouhal number was changed, and the operation was continued for 30 minutes to produce the aggregate "B" o...

example 2

[0084] Example 2: Measurement of Bulk Density

[0085] Bulk density is measured by the following method. A weight amount W of "as received" resin is placed in a dry scaled cylinder. Tap the resin sample gently to a constant volume V. The bulk density is calculated as follows:

[0086] Bulk density (kg / m 3 )=1000X W(g) / V(ml)

[0087] A comparative sample (comparative 2) is as follows. The resin bead composition of the polymer was 90 parts by weight styrene and 10 parts by weight divinylbenzene (a mixture of 63% divinylbenzene and 27% ethylvinylbenzene); the harmonic mean diameter was 490 μm, and the coefficient of uniformity was 1.05.

[0088] The bulk density is as follows:

[0089] sample Bulk density Example 1 650kg / m 3 (40.6lb / ft 3 )

[0090] The example polymeric beads have a higher packing density than the comparative polymeric beads.

example 3

[0091] Example 3: Preparation of Another Example Distribution

[0092] A suspension of droplets suspended in an aqueous medium is prepared using a procedure similar to that described by US 4,444,960.

[0093] A monomer mixture comprising 83.9 parts by weight styrene, 15.8 parts by weight divinylbenzene (a mixture of 63% divinylbenzene and 27% ethylvinylbenzene) and 0.17 parts by weight peroxide initiator was passed through an orifice plate ( The plate had two openings (each having a diameter of 199 μm)) into which the openings were metered into the monomer reservoirs in five different sequential conditions as listed in the table below for a total of 1007 minutes. As defined in US 4,444,960 and using Reynolds numbers and Strouhal numbers. The flow rate was 6.5ml / min and the Reynolds number was 313 for all five conditions.

[0094]

[0095] Hold each condition for 20 minutes, then change only the Strouhal number, and hold the next condition for 20 minutes to generate new ag...

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Abstract

A method of preparing a collection of polymeric beads is provided, the method comprising (a1) forming a first collection of monomer droplets in an aqueous medium in a vessel, wherein the first collection of monomer droplets has a volume average having a diameter DAV1 and having a uniformity coefficient less than (1.3); (a2) forming a second aggregate of monomer droplets in the aqueous medium in the vessel, wherein the second aggregate of monomer droplets has a volume average diameter DAV2 and having a uniformity coefficient less than (1.3), wherein DAV1 and DAV2 differ by (10) μm or more; wherein step (a1) and step (a2) are carried out simultaneously; or after step (a1) in the first step of the monomer droplet performing step (a2); or a combination thereof while the aggregate remains in the container; and (b) polymerizing the monomer droplets by suspension polymerization to form polymer beads after steps (a1 ) and (a2).

Description

technical field [0001] When considering an aggregate of polymeric beads, it is important to consider the particle size distribution within the aggregate. Polymer beads produced by aqueous suspension polymerization generally have a particle size distribution that is unimodal. That is, when plotting particle occurrence versus diameter, only a single significant peak was observed. In such cases, the peak is usually approximated by a Gaussian distribution, where the appearance as a function of the diameter (d) corresponds to the function exp(-(d-μ) 2 / (2σ 2 )) proportional, where μ is the mean and σ is the standard deviation. Such particle size distributions are also characterized by a coefficient of uniformity ("UC", defined below). A unimodal distribution with a UC greater than 1.5 is referred to herein as "typically Gaussian", while a unimodal distribution with a UC less than 1.3 is referred to herein as "uniform". Background technique [0002] A disadvantage associated ...

Claims

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Application Information

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IPC IPC(8): C08F2/18C08F12/08C08F20/10C08F20/68C08L33/04
CPCC08F20/10C08F2/18C08F212/08C08F212/36C08F12/08C08F2800/20C08F20/14
Inventor J·D·芬奇J·A·加格德金斯基
Owner DDP特种电子材料美国有限责任公司