# Bold symbol in math mode: \boldsymbol + \mathrm don't work

I am writing an article with given LaTeX template. Usually, when I want to type vector as bold non-italic letter, I use command

\boldsymbol{ \mathrm{ \Phi} }


which works perfectly with basic amsmath included. This does not work, however, for provided template. \boldsymbol command gets negleted. I know I can use different approaches, such as \mathbf or \bm, but I would like to know what causes such behaviour. In case it was useful, I present code of the template:

\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{sth}[2016/04/21]
\DeclareOption*{\PassOptionsToClass{\CurrentOption}{article}}
\ProcessOptions

\usepackage[margin=25mm]{geometry}% <-------- CHANGE HERE for the global margins
\usepackage{mathptmx} % for Times

\renewenvironment{maketitle}{
\setlength{\leftmargin}{0mm}% <---------- CHANGE HERE
\setlength{\topmargin}{0mm}
\vspace{7mm}\hspace{-5mm}\@author\vspace{11.25mm}
\renewcommand{\rmdefault}{phv} % Arial
\normalfont
\fontsize{20}{22.65}
\selectfont
\begin{center}
\@title\relax\end{center}\vspace{-6.45mm}
\renewcommand{\familydefault}{\rmdefault}
\normalfont
\fontsize{12}{14}\selectfont\thispagestyle{firstpage}}
\usepackage{setspace}

\renewenvironment{abstract}
{\small
\begin{center}
\end{center}
\list{}{%
\setlength{\leftmargin}{40mm}% <---------- CHANGE HERE
\setlength{\rightmargin}{0mm}%
\setstretch{1}
}%
\fontsize{10}{4mm}
\selectfont
\item\relax\vspace{-5mm}}
{\endlist}

\renewcommand{\thesection}{\fontsize{14}{5mm}\arabic{section}.}
\renewcommand{\thesubsection}{\thesection\fontsize{14}{5mm}\arabic{subsection}.}
\renewcommand{\thesubsubsection}{\thesubsection\fontsize{14}{5mm}\arabic{subsubsection}.}

\usepackage{sectsty}

\sectionfont{
\renewcommand{\rmdefault}{phv} % Arial
\renewcommand{\sfdefault}{phv} % Arial
\fontsize{14}{5mm}\selectfont}

\usepackage{mathptmx}
\usepackage{helvet}
\renewcommand{\familydefault}{\rmdefault}
\normalfont
\fontsize{12}{13.6}\selectfont
\usepackage{indentfirst}
\setlength{\parindent}{5mm}
\setlength{\parskip}{5.65pt}
\usepackage{titlesec}
\titlespacing*{\section}{-7pt}{19.8pt}{1.4pt}
\usepackage{authblk}
\renewcommand\Authfont{\fontsize{12}{14}\selectfont}
\renewcommand{\baselinestretch}{1}
\makeatletter
\renewcommand*{\@seccntformat}[1]{\csname the#1\endcsname\hspace{4pt}}
\renewcommand\@biblabel[1]{#1.}
\makeatother
\setstretch{1}
\setlength{\abovecaptionskip}{6mm plus 3pt minus 2pt}
\setlength{\belowcaptionskip}{1.5mm plus 3pt minus 2pt}
\usepackage[font=footnotesize,labelfont=footnotesize]{caption}
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancypagestyle{firstpage}{
}
\fancyhf{}

• (1) Please always post a complete, compilable, minimal working example (MWE) which we can copy, paste, and compile to reproduce your problem. (2) \boldsymbol is defined by the amsmath package, so if you don't load that, \boldsymbol will not be available. – Henri Menke Jun 25 '17 at 22:29
• mathptmx is a very basic and old emulation of times for math and does not provide bold fonts. – David Carlisle Jun 25 '17 at 23:24
• It's been a while, but this actually has done the trick! If you posted your answer, I would gladly accept it :) – Maverick Jan 16 '19 at 12:56

\mathrm{} is useless in your example.

\documentclass{article}

\usepackage{amsmath} %for \boldsymbol

\begin{document}

Normal Phi: $\Phi$

Bold Phi: $\boldsymbol\Phi$

\end{document}